a case study on pollution

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• My Account Login
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• Open access
• Published: 29 October 2020

Urban and air pollution: a multi-city study of long-term effects of urban landscape patterns on air quality trends

• Lu Liang 1 &
• Peng Gong 2 , 3 , 4  

Scientific Reports volume  10 , Article number:  18618 ( 2020 ) Cite this article

59k Accesses

103 Citations

320 Altmetric

Metrics details

• Environmental impact
• Environmental sciences

Most air pollution research has focused on assessing the urban landscape effects of pollutants in megacities, little is known about their associations in small- to mid-sized cities. Considering that the biggest urban growth is projected to occur in these smaller-scale cities, this empirical study identifies the key urban form determinants of decadal-long fine particulate matter (PM 2.5 ) trends in all 626 Chinese cities at the county level and above. As the first study of its kind, this study comprehensively examines the urban form effects on air quality in cities of different population sizes, at different development levels, and in different spatial-autocorrelation positions. Results demonstrate that the urban form evolution has long-term effects on PM 2.5 level, but the dominant factors shift over the urbanization stages: area metrics play a role in PM 2.5 trends of small-sized cities at the early urban development stage, whereas aggregation metrics determine such trends mostly in mid-sized cities. For large cities exhibiting a higher degree of urbanization, the spatial connectedness of urban patches is positively associated with long-term PM 2.5 level increases. We suggest that, depending on the city’s developmental stage, different aspects of the urban form should be emphasized to achieve long-term clean air goals.

Similar content being viewed by others

Impact of urban agglomeration construction on urban air quality–empirical test based on PSM–DID model

Wanxiong Zhang, Ruiyun Cui, … Xueqiong Tang

Spatiotemporal variations of air pollutants based on ground observation and emission sources over 19 Chinese urban agglomerations during 2015–2019

Tianhui Tao, Yishao Shi, … Xinyi Liu

Particulate matter-attributable mortality and relationships with carbon dioxide in 250 urban areas worldwide

Susan C. Anenberg, Pattanun Achakulwisut, … Daven K. Henze

Introduction

Air pollution represents a prominent threat to global society by causing cascading effects on individuals 1 , medical systems 2 , ecosystem health 3 , and economies 4 in both developing and developed countries 5 , 6 , 7 , 8 . About 90% of global citizens lived in areas that exceed the safe level in the World Health Organization (WHO) air quality guidelines 9 . Among all types of ecosystems, urban produce roughly 78% of carbon emissions and substantial airborne pollutants that adversely affect over 50% of the world’s population living in them 5 , 10 . While air pollution affects all regions, there exhibits substantial regional variation in air pollution levels 11 . For instance, the annual mean concentration of fine particulate matter with an aerodynamic diameter of less than 2.5  \(\upmu\mathrm{m}\) (PM 2.5 ) in the most polluted cities is nearly 20 times higher than the cleanest city according to a survey of 499 global cities 12 . Many factors can influence the regional air quality, including emissions, meteorology, and physicochemical transformations. Another non-negligible driver is urbanization—a process that alters the size, structure, and growth of cities in response to the population explosion and further leads to lasting air quality challenges 13 , 14 , 15 .

With the global trend of urbanization 16 , the spatial composition, configuration, and density of urban land uses (refer to as urban form) will continue to evolve 13 . The investigation of urban form impacts on air quality has been emerging in both empirical 17 and theoretical 18 research. While the area and density of artificial surface areas have well documented positive relationship with air pollution 19 , 20 , 21 , the effects of urban fragmentation on air quality have been controversial. In theory, compact cities promote high residential density with mixed land uses and thus reduce auto dependence and increase the usage of public transit and walking 21 , 22 . The compact urban development has been proved effective in mitigating air pollution in some cities 23 , 24 . A survey of 83 global urban areas also found that those with highly contiguous built-up areas emitted less NO 2 22 . In contrast, dispersed urban form can decentralize industrial polluters, improve fuel efficiency with less traffic congestion, and alleviate street canyon effects 25 , 26 , 27 , 28 . Polycentric and dispersed cities support the decentralization of jobs that lead to less pollution emission than compact and monocentric cities 29 . The more open spaces in a dispersed city support air dilution 30 . In contrast, compact cities are typically associated with stronger urban heat island effects 31 , which influence the availability and the advection of primary and secondary pollutants 32 .

The mixed evidence demonstrates the complex interplay between urban form and air pollution, which further implies that the inconsistent relationship may exist in cities at different urbanization levels and over different periods 33 . Few studies have attempted to investigate the urban form–air pollution relationship with cross-sectional and time series data 34 , 35 , 36 , 37 . Most studies were conducted in one city or metropolitan region 38 , 39 or even at the country level 40 . Furthermore, large cities or metropolitan areas draw the most attention in relevant studies 5 , 41 , 42 , and the small- and mid-sized cities, especially those in developing countries, are heavily underemphasized. However, virtually all world population growth 43 , 44 and most global economic growth 45 , 46 are expected to occur in those cities over the next several decades. Thus, an overlooked yet essential task is to account for various levels of cities, ranging from large metropolitan areas to less extensive urban area, in the analysis.

This study aims to improve the understanding of how the urban form evolution explains the decadal-long changes of the annual mean PM 2.5 concentrations in 626 cities at the county-level and above in China. China has undergone unprecedented urbanization over the past few decades and manifested a high degree of heterogeneity in urban development 47 . Thus, Chinese cities serve as a good model for addressing the following questions: (1) whether the changes in urban landscape patterns affect trends in PM 2.5 levels? And (2) if so, do the determinants vary by cities?

City boundaries

Our study period spans from the year 2000 to 2014 to keep the data completeness among all data sources. After excluding cities with invalid or missing PM 2.5 or sociodemographic value, a total of 626 cities, with 278 prefecture-level cities and 348 county-level cities, were selected. City boundaries are primarily based on the Global Rural–Urban Mapping Project (GRUMP) urban extent polygons that were defined by the extent of the nighttime lights 48 , 49 . Few adjustments were made. First, in the GRUMP dataset, large agglomerations that include several cities were often described in one big polygon. We manually split those polygons into individual cities based on the China Administrative Regions GIS Data at 1:1 million scales 50 . Second, since the 1978 economic reforms, China has significantly restructured its urban administrative/spatial system. Noticeable changes are the abolishment of several prefectures and the promotion of many former county-level cities to prefecture-level cities 51 . Thus, all city names were cross-checked between the year 2000 and 2014, and the mismatched records were replaced with the latest names.

PM 2.5 concentration data

The annual mean PM 2.5 surface concentration (micrograms per cubic meter) for each city over the study period was calculated from the Global Annual PM 2.5 Grids at 0.01° resolution 52 . This data set combines Aerosol Optical Depth retrievals from multiple satellite instruments including the NASA Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging SpectroRadiometer (MISR), and the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS). The global 3-D chemical transport model GEOS-Chem is further applied to relate this total column measure of aerosol to near-surface PM 2.5 concentration, and geographically weighted regression is finally used with global ground-based measurements to predict and adjust for the residual PM 2.5 bias per grid cell in the initial satellite-derived values.

Human settlement layer

The urban forms were quantified with the 40-year (1978–2017) record of annual impervious surface maps for both rural and urban areas in China 47 , 53 . This state-of-art product provides substantial spatial–temporal details on China’s human settlement changes. The annual impervious surface maps covering our study period were generated from 30-m resolution Landsat images acquired onboard Landsat 5, 7, and 8 using an automatic “Exclusion/Inclusion” mapping framework 54 , 55 . The output used here was the binary impervious surface mask, with the value of one indicating the presence of human settlement and the value of zero identifying non-residential areas. The product assessment concluded good performance. The cross-comparison against 2356 city or town locations in GeoNames proved an overall high agreement (88%) and approximately 80% agreement was achieved when compared against visually interpreted 650 urban extent areas in the year 1990, 2000, and 2010.

Control variables

To provide a holistic assessment of the urban form effects, we included control variables that are regarded as important in influencing air quality to account for the confounding effects.

Four variables, separately population size, population density, and two economic measures, were acquired from the China City Statistical Yearbook 56 (National Bureau of Statistics 2000–2014). Population size is used to control for the absolute level of pollution emissions 41 . Larger populations are associated with increased vehicle usage and vehicle-kilometers travels, and consequently boost tailpipes emissions 5 . Population density is a useful reflector of transportation demand and the fraction of emissions inhaled by people 57 . We also included gross regional product (GRP) and the proportion of GRP generated from the secondary sector (GRP2). The impact of economic development on air quality is significant but in a dynamic way 58 . The rising per capita income due to the concentration of manufacturing industrial activities can deteriorate air quality and vice versa if the stronger economy is the outcome of the concentration of less polluting high-tech industries. Meteorological conditions also have short- and long-term effects on the occurrence, transport, and dispersion of air pollutants 59 , 60 , 61 . Temperature affects chemical reactions and atmospheric turbulence that determine the formation and diffusion of particles 62 . Low air humidity can lead to the accumulation of air pollutants due to it is conducive to the adhesion of atmospheric particulate matter on water vapor 63 . Whereas high humidity can lead to wet deposition processes that can remove air pollutants by rainfall. Wind speed is a crucial indicator of atmospheric activity by greatly affect air pollutant transport and dispersion. All meteorological variables were calculated based on China 1 km raster layers of monthly relative humidity, temperature, and wind speed that are interpolated from over 800 ground monitoring stations 64 . Based on the monthly layer, we calculated the annual mean of each variable for each year. Finally, all pixels falling inside of the city boundary were averaged to represent the overall meteorological condition of each city.

Considering the dynamic urban form-air pollution relationship evidenced from the literature review, our hypothesis is: the determinants of PM 2.5 level trends are not the same for cities undergoing different levels of development or in different geographic regions. To test this hypothesis, we first categorized city groups following (1) social-economic development level, (2) spatial autocorrelation relationship, and (3) population size. We then assessed the relationship between urban form and PM 2.5 level trends by city groups. Finally, we applied the panel data models to different city groups for hypothesis testing and key determinant identification (Fig.  1 ).

Methodology workflow.

Calculation of urban form metrics

Based on the previous knowledge 65 , 66 , 67 , fifteen landscape metrics falling into three categories, separately area, shape, and aggregation, were selected. Those metrics quantify the compositional and configurational characteristics of the urban landscape, as represented by urban expansion, urban shape complexity, and compactness (Table 1 ).

Area metrics gives an overview of the urban extent and the size of urban patches that are correlated with PM 2.5 20 . As an indicator of the urbanization degree, total area (TA) typically increases constantly or remains stable, because the urbanization process is irreversible. Number of patches (NP) refers to the number of discrete parcels of urban settlement within a given urban extent and Mean Patch Size (AREA_MN) measures the average patch size. Patch density (PD) indicates the urbanization stages. It usually increases with urban diffusion until coalescence starts, after which decreases in number 66 . Largest Patch Index (LPI) measures the percentage of the landscape encompassed by the largest urban patch.

The shape complexity of urban patches was represented by Mean Patch Shape Index (SHAPE_MN), Mean Patch Fractal Dimension (FRAC_MN), and Mean Contiguity Index (CONTIG_MN). The greater irregularity the landscape shape, the larger the value of SHAPE_MN and FRAC_MN. CONTIG_MN is another method of assessing patch shape based on the spatial connectedness or contiguity of cells within a patch. Larger contiguous patches will result in larger CONTIG_MN.

Aggregation metrics measure the spatial compactness of urban land, which affects pollutant diffusion and dilution. Mean Euclidean nearest-neighbor distance (ENN_MN) quantifies the average distance between two patches within a landscape. It decreases as patches grow together and increases as the urban areas expand. Landscape Shape Index (LSI) indicates the divergence of the shape of a landscape patch that increases as the landscape becomes increasingly disaggregated 68 . Patch Cohesion Index (COHESION) is suggestive of the connectedness degree of patches 69 . Splitting Index (SPLIT) and Landscape Division Index (DIVISION) increase as the separation of urban patches rises, whereas, Mesh Size (MESH) decreases as the landscape becomes more fragmented. Aggregation Index (AI) measures the degree of aggregation or clumping of urban patches. Higher values of continuity indicate higher building densities, which may have a stronger effect on pollution diffusion.

The detailed descriptions of these indices are given by the FRAGSTATS user’s guide 70 . The calculation input is a layer of binary grids of urban/nonurban. The resulting output is a table containing one row for each city and multiple columns representing the individual metrics.

Division of cities

Division based on the socioeconomic development level.

The socioeconomic development level in China is uneven. The unequal development of the transportation system, descending in topography from the west to the east, combined with variations in the availability of natural and human resources and industrial infrastructure, has produced significantly wide gaps in the regional economies of China. By taking both the economic development level and natural geography into account, China can be loosely classified into Eastern, Central, and Western regions. Eastern China is generally wealthier than the interior, resulting from closeness to coastlines and the Open-Door Policy favoring coastal regions. Western China is historically behind in economic development because of its high elevation and rugged topography, which creates barriers in the transportation infrastructure construction and scarcity of arable lands. Central China, echoing its name, is in the process of economic development. This region neither benefited from geographic convenience to the coast nor benefited from any preferential policies, such as the Western Development Campaign.

Division based on spatial autocorrelation relationship

The second type of division follows the fact that adjacent cities are likely to form air pollution clusters due to the mixing and diluting nature of air pollutants 71 , i.e., cities share similar pollution levels as its neighbors. The underlying processes driving the formation of pollution hot spots and cold spots may differ. Thus, we further divided the city into groups based on the spatial clusters of PM 2.5 level changes.

Local indicators of spatial autocorrelation (LISA) was used to determine the local patterns of PM 2.5 distribution by clustering cities with a significant association. In the presence of global spatial autocorrelation, LISA indicates whether a variable exhibits significant spatial dependence and heterogeneity at a given scale 72 . Practically, LISA relates each observation to its neighbors and assigns a value of significance level and degree of spatial autocorrelation, which is calculated by the similarity in variable \(z\) between observation \(i\) and observation \(j\) in the neighborhood of \(i\) defined by a matrix of weights \({w}_{ij}\) 7 , 73 :

where \({I}_{i}\) is the Moran’s I value for location \(i\) ; \({\sigma }^{2}\) is the variance of variable \(z\) ; \(\bar{z}\) is the average value of \(z\) with the sample number of \(n\) . The weight matrix \({w}_{ij}\) is defined by the k-nearest neighbors distance measure, i.e., each object’s neighborhood consists of four closest cites.

The computation of Moran’s I enables the identification of hot spots and cold spots. The hot spots are high-high clusters where the increase in the PM 2.5 level is higher than the surrounding areas, whereas cold spots are low-low clusters with the presence of low values in a low-value neighborhood. A Moran scatterplot, with x-axis as the original variable and y-axis as the spatially lagged variable, reflects the spatial association pattern. The slope of the linear fit to the scatter plot is an estimation of the global Moran's I 72 (Fig.  2 ). The plot consists of four quadrants, each defining the relationship between an observation 74 . The upper right quadrant indicates hot spots and the lower left quadrant displays cold spots 75 .

Moran’s I scatterplot. Figure was produced by R 3.4.3 76 .

Division based on population size

The last division was based on population size, which is a proven factor in changing per capita emissions in a wide selection of global cities, even outperformed land urbanization rate 77 , 78 , 79 . We used the 2014 urban population to classify the cities into four groups based on United Nations definitions 80 : (1) large agglomerations with a total population larger than 1 million; (2) mid-sized cities, 500,000–1 million; (3) small cities, 250,000–500,000, and (4) very small cities, 100,000–250,000.

Panel data analysis

The panel data analysis is an analytical method that deals with observations from multiple entities over multiple periods. Its capacity in analyzing the characteristics and changes from both the time-series and cross-section dimensions of data surpasses conventional models that purely focus on one dimension 81 , 82 . The estimation equation for the panel data model in this study is given as:

where the subscript \(i\) and \(t\) refer to city and year respectively. \(\upbeta _{{0}}\) is the intercept parameter and \(\upbeta _{{1}} - { }\upbeta _{{{18}}}\) are the estimates of slope coefficients. \(\varepsilon \) is the random error. All variables are transformed into natural logarithms.

Two methods can be used to obtain model estimates, separately fixed effects estimator and random effects estimator. The fixed effects estimator assumes that each subject has its specific characteristics due to inherent individual characteristic effects in the error term, thereby allowing differences to be intercepted between subjects. The random effects estimator assumes that the individual characteristic effect changes stochastically, and the differences in subjects are not fixed in time and are independent between subjects. To choose the right estimator, we run both models for each group of cities based on the Hausman specification test 83 . The null hypothesis is that random effects model yields consistent and efficient estimates 84 : \({H}_{0}{:}\,E\left({\varepsilon }_{i}|{X}_{it}\right)=0\) . If the null hypothesis is rejected, the fixed effects model will be selected for further inferences. Once the better estimator was determined for each model, one optimal panel data model was fit to each city group of one division type. In total, six, four, and eight runs were conducted for socioeconomic, spatial autocorrelation, and population division separately and three, two, and four panel data models were finally selected.

Spatial patterns of PM 2.5 level changes

During the period from 2000 to 2014, the annual mean PM 2.5 concentration of all cities increases from 27.78 to 42.34 µg/m 3 , both of which exceed the World Health Organization recommended annual mean standard (10 µg/m 3 ). It is worth noting that the PM 2.5 level in the year 2014 also exceeds China’s air quality Class 2 standard (35 µg/m 3 ) that applies to non-national park places, including urban and industrial areas. The standard deviation of annual mean PM 2.5 values for all cities increases from 12.34 to 16.71 µg/m 3 , which shows a higher variability of inter-urban PM 2.5 pollution after a decadal period. The least and most heavily polluted cities in China are Delingha, Qinghai (3.01 µg/m 3 ) and Jizhou, Hubei (64.15 µg/m 3 ) in 2000 and Hami, Xinjiang (6.86 µg/m 3 ) and Baoding, Hubei (86.72 µg/m 3 ) in 2014.

Spatially, the changes in PM 2.5 levels exhibit heterogeneous patterns across cities (Fig.  3 b). According to the socioeconomic level division (Fig.  3 a), the Eastern, Central, and Western region experienced a 38.6, 35.3, and 25.5 µg/m 3 increase in annual PM 2.5 mean , separately, and the difference among regions is significant according to the analysis of variance (ANOVA) results (Fig.  4 a). When stratified by spatial autocorrelation relationship (Fig.  3 c), the differences in PM 2.5 changes among the spatial clusters are even more dramatic. The average PM 2.5 increase in cities belonging to the high-high cluster is approximately 25 µg/m 3 , as compared to 5 µg/m 3 in the low-low clusters (Fig.  4 b). Finally, cities at four different population levels have significant differences in the changes of PM 2.5 concentration (Fig.  3 d), except for the mid-sized cities and large city agglomeration (Fig.  4 c).

( a ) Division of cities in China by socioeconomic development level and the locations of provincial capitals; ( b ) Changes in annual mean PM 2.5 concentrations between the year 2000 and 2014; ( c ) LISA cluster maps for PM 2.5 changes at the city level; High-high indicates a statistically significant cluster of high PM 2.5 level changes over the study period. Low-low indicates a cluster of low PM 2.5 inter-annual variation; No high-low cluster is reported; Low–high represents cities with high PM 2.5 inter-annual variation surrounded by cities with low variation; ( d ) Population level by cities in the year 2014. Maps were produced by ArcGIS 10.7.1 85 .

Boxplots of PM 2.5 concentration changes between 2000 and 2014 for city groups that are formed according to ( a ) socioeconomic development level division, ( b ) LISA clusters, and ( c ) population level. Asterisk marks represent the p value of ANOVA significant test between the corresponding pair of groups. Note ns not significant; * p value < 0.05; ** p value < 0.01; *** p value < 0.001; H–H high-high cluster, L–H low–high cluster, L–L denotes low–low cluster.

The effects of urban forms on PM 2.5 changes

The Hausman specification test for fixed versus random effects yields a p value less than 0.05, suggesting that the fixed effects model has better performance. We fit one panel data model to each city group and built nine models in total. All models are statistically significant at the p  < 0.05 level and have moderate to high predictive power with the R 2 values ranging from 0.63 to 0.95, which implies that 63–95% of the variation in the PM 2.5 concentration changes can be explained by the explanatory variables (Table 2 ).

The urban form—PM 2.5 relationships differ distinctly in Eastern, Central, and Western China. All models reach high R 2 values. Model for Eastern China (refer to hereafter as Eastern model) achieves the highest R 2 (0.90), and the model for the Western China (refer to hereafter as Western model) reaches the lowest R 2 (0.83). The shape metrics FRAC and CONTIG are correlated with PM 2.5 changes in the Eastern model, whereas the area metrics AREA demonstrates a positive effect in the Western model. In contrast to the significant associations between shape, area metrics and PM 2.5 level changes in both Eastern and Western models, no such association was detected in the Central model. Nonetheless, two aggregation metrics, LSI and AI, play positive roles in determining the PM 2.5 trends in the Central model.

For models built upon the LISA clusters, the H–H model (R 2  = 0.95) reaches a higher fitting degree than the L–L model (R 2  = 0.63). The estimated coefficients vary substantially. In the H–H model, the coefficient of CONTIG is positive, which indicates that an increase in CONTIG would increase PM 2.5 pollution. In contrast, no shape metrics but one area metrics AREA is significant in the L–L model.

The results of the regression models built for cities at different population levels exhibit a distinct pattern. No urban form metrics was identified to have a significant relationship with the PM 2.5 level changes in groups of very small and mid-sized cities. For small size cities, the aggregation metrics COHESION was positively associated whereas AI was negatively related. For mid-sized cities and large agglomerations, CONTIG is the only significant variable that is positively related to PM 2.5 level changes.

Urban form is an effective measure of long-term PM 2.5 trends

All panel data models are statistically significant regardless of the data group they are built on, suggesting that the associations between urban form and ambient PM 2.5 level changes are discernible at all city levels. Importantly, these relationships are found to hold when controlling for population size and gross domestic product, implying that the urban landscape patterns have effects on long-term PM 2.5 trends that are independent of regional economic performance. These findings echo with the local, regional, and global evidence of urban form effect on various air pollution types 5 , 14 , 21 , 22 , 24 , 39 , 78 .

Although all models demonstrate moderate to high predictive power, the way how different urban form metrics respond to the dependent variable varies. Of all the metrics tested, shape metrics, especially CONTIG has the strongest effect on PM 2.5 trends in cities belonging to the high-high cluster, Eastern, and large urban agglomerations. All those regions have a strong economy and higher population density 86 . In the group of cities that are moderately developed, such as the Central region, as well as small- and mid-sized cities, aggregation metrics play a dominant negative role in PM 2.5 level changes. In contrast, in the least developed cities belonging to the low-low cluster regions and Western China, the metrics describing size and number of urban patches are the strongest predictors. AREA and NP are positively related whereas TA is negatively associated.

The impacts of urban form metrics on air quality vary by urbanization degree

Based on the above observations, how urban form affects within-city PM 2.5 level changes may differ over the urbanization stages. We conceptually summarized the pattern in Fig.  5 : area metrics have the most substantial influence on air pollution changes at the early urban development stage, and aggregation metrics emerge at the transition stage, whereas shape metrics affect the air quality trends at the terminal stage. The relationship between urban form and air pollution has rarely been explored with such a wide range of city selections. Most prior studies were focused on large urban agglomeration areas, and thus their conclusions are not representative towards small cities at the early or transition stage of urbanization.

The most influential metric of urban form in affecting PM 2.5 level changes at different urbanization stages.

Not surprisingly, the area metrics, which describe spatial grain of the landscape, exert a significant effect on PM 2.5 level changes in small-sized cities. This could be explained by the unusual urbanization speed of small-sized cities in the Chinese context. Their thriving mostly benefited from the urbanization policy in the 1980s, which emphasized industrialization of rural, small- and mid-sized cities 87 . With the large rural-to-urban migration and growing public interest in investing real estate market, a side effect is that the massive housing construction that sometimes exceeds market demand. Residential activities decline in newly built areas of smaller cities in China, leading to what are known as ghost cities 88 . Although ghost cities do not exist for all cities, high rate of unoccupied dwellings is commonly seen in cities under the prefectural level. This partly explained the negative impacts of TA on PM 2.5 level changes, as an expanded while unoccupied or non-industrialized urban zones may lower the average PM 2.5 concentration within the city boundary, but it doesn’t necessarily mean that the air quality got improved in the city cores.

Aggregation metrics at the landscape scale is often referred to as landscape texture that quantifies the tendency of patch types to be spatially aggregated; i.e., broadly speaking, aggregated or “contagious” distributions. This group of metrics is most effective in capturing the PM 2.5 trends in mid-sized cities (population range 25–50 k) and Central China, where the urbanization process is still undergoing. The three significant variables that reflect the spatial property of dispersion, separately landscape shape index, patch cohesion index, and aggregation index, consistently indicate that more aggregated landscape results in a higher degree of PM 2.5 level changes. Theoretically, the more compact urban form typically leads to less auto dependence and heavier reliance on the usage of public transit and walking, which contributes to air pollution mitigation 89 . This phenomenon has also been observed in China, as the vehicle-use intensity (kilometers traveled per vehicle per year, VKT) has been declining over recent years 90 . However, VKT only represents the travel intensity of one car and does not reflect the total distance traveled that cumulatively contribute to the local pollution. It should be noted that the private light-duty vehicle ownership in China has increased exponentially and is forecast to reach 23–42 million by 2050, with the share of new-growth purchases representing 16–28% 90 . In this case, considering the increased total distance traveled, the less dispersed urban form can exert negative effects on air quality by concentrating vehicle pollution emissions in a limited space.

Finally, urban contiguity, observed as the most effective shape metric in indicating PM 2.5 level changes, provides an assessment of spatial connectedness across all urban patches. Urban contiguity is found to have a positive effect on the long-term PM 2.5 pollution changes in large cities. Urban contiguity reflects to which degree the urban landscape is fragmented. Large contiguous patches result in large CONTIG_MN values. Among the 626 cities, only 11% of cities experience negative changes in urban contiguity. For example, Qingyang, Gansu is one of the cities-featuring leapfrogs and scattered development separated by vacant land that may later be filled in as the development continues (Fig.  6 ). Most Chinese cities experienced increased urban contiguity, with less fragmented and compacted landscape. A typical example is Shenzhou, Hebei, where CONTIG_MN rose from 0.27 to 0.45 within the 14 years. Although the 13 counties in Shenzhou are very far scattered from each other, each county is growing intensively internally rather than sprawling further outside. And its urban layout is thus more compact (Fig.  6 ). The positive association revealed in this study contradicts a global study indicating that cities with highly contiguous built-up areas have lower NO 2 pollution 22 . We noticed that the principal emission sources of NO 2 differ from that of PM 2.5. NO 2 is primarily emitted with the combustion of fossil fuels (e.g., industrial processes and power generation) 6 , whereas road traffic attributes more to PM 2.5 emissions. Highly connected urban form is likely to cause traffic congestion and trap pollution inside the street canyon, which accumulates higher PM 2.5 concentration. Computer simulation results also indicate that more compact cities improve urban air quality but are under the premise that mixed land use should be presented 18 . With more connected impervious surfaces, it is merely impossible to expect increasing urban green spaces. If compact urban development does not contribute to a rising proportion of green areas, then such a development does not help mitigating air pollution 41 .

Six cities illustrating negative to positive changes in CONTIG_MN and AREA_MN. Pixels in black show the urban areas in the year 2000 and pixels in red are the expanded urban areas from the year 2000 to 2014. Figure was produced by ArcGIS 10.7.1 85 .

Conclusions

This study explores the regional land-use patterns and air quality in a country with an extraordinarily heterogeneous urbanization pattern. Our study is the first of its kind in investigating such a wide range selection of cities ranging from small-sized ones to large metropolitan areas spanning a long time frame, to gain a comprehensive insight into the varying effects of urban form on air quality trends. And the primary insight yielded from this study is the validation of the hypothesis that the determinants of PM 2.5 level trends are not the same for cities at various developmental levels or in different geographic regions. Certain measures of urban form are robust predictors of air quality trends for a certain group of cities. Therefore, any planning strategy aimed at reducing air pollution should consider its current development status and based upon which, design its future plan. To this end, it is also important to emphasize the main shortcoming of this analysis, which is generally centered around the selection of control variables. This is largely constrained by the available information from the City Statistical Yearbook. It will be beneficial to further polish this study by including other important controlling factors, such as vehicle possession.

Lim, C. C. et al. Association between long-term exposure to ambient air pollution and diabetes mortality in the US. Environ. Res. 165 , 330–336 (2018).

Article   CAS   PubMed   PubMed Central   Google Scholar  

Yang, J. & Zhang, B. Air pollution and healthcare expenditure: implication for the benefit of air pollution control in China. Environ. Int. 120 , 443–455 (2018).

Article   PubMed   Google Scholar  

Bell, J. N. B., Power, S. A., Jarraud, N., Agrawal, M. & Davies, C. The effects of air pollution on urban ecosystems and agriculture. Int. J. Sust. Dev. World 18 (3), 226–235 (2011).

Article   Google Scholar  

Matus, K. et al. Health damages from air pollution in China. Glob. Environ. Change 22 (1), 55–66 (2012).

Bereitschaft, B. & Debbage, K. Urban form, air pollution, and CO 2 emissions in large US metropolitan areas. Prof Geogr. 65 (4), 612–635 (2013).

Bozkurt, Z., Üzmez, Ö. Ö., Döğeroğlu, T., Artun, G. & Gaga, E. O. Atmospheric concentrations of SO2, NO2, ozone and VOCs in Düzce, Turkey using passive air samplers: sources, spatial and seasonal variations and health risk estimation. Atmos. Pollut. Res. 9 (6), 1146–1156 (2018).

Article   CAS   Google Scholar  

Fang, C., Liu, H., Li, G., Sun, D. & Miao, Z. Estimating the impact of urbanization on air quality in China using spatial regression models. Sustainability 7 (11), 15570–15592 (2015).

Khaniabadi, Y. O. et al. Mortality and morbidity due to ambient air pollution in Iran. Clin. Epidemiol. Glob. Health 7 (2), 222–227 (2019).

Health Effects Institute. State of Global Air 2019 . Special Report (Health Effects Institute, Boston, 2019). ISSN 2578-6873.

O’Meara, M. & Peterson, J. A. Reinventing Cities for People and the Planet (Worldwatch Institute, Washington, 1999).

Google Scholar  

World Health Organization. Ambient Air Pollution: A Global Assessment of Exposure and Burden of Disease . ISBN: 9789241511353 (2016).

Liu, C. et al. Ambient particulate air pollution and daily mortality in 652 cities. N. Engl. J. Med. 381 (8), 705–715 (2019).

Anderson, W. P., Kanaroglou, P. S. & Miller, E. J. Urban form, energy and the environment: a review of issues, evidence and policy. Urban Stud. 33 (1), 7–35 (1996).

Hart, R., Liang, L. & Dong, P. L. Monitoring, mapping, and modeling spatial–temporal patterns of PM2.5 for improved understanding of air pollution dynamics using portable sensing technologies. Int. J. Environ. Res. Public Health . 17 (14), 4914 (2020).

Article   PubMed Central   Google Scholar  

Environmental Protection Agency. Our Built and Natural Environments: A Technical Review of the Interactions Between Land Use, Transportation and Environmental Quality (2nd edn.). Report 231K13001 (Environmental Protection Agency, Washington, 2013).

Chen, M., Zhang, H., Liu, W. & Zhang, W. The global pattern of urbanization and economic growth: evidence from the last three decades. PLoS ONE 9 (8), e103799 (2014).

Article   ADS   PubMed   PubMed Central   CAS   Google Scholar  

Wang, S., Liu, X., Zhou, C., Hu, J. & Ou, J. Examining the impacts of socioeconomic factors, urban form, and transportation networks on CO 2 emissions in China’s megacities. Appl. Energy. 185 , 189–200 (2017).

Borrego, C. et al. How urban structure can affect city sustainability from an air quality perspective. Environ. Model. Softw. 21 (4), 461–467 (2006).

Bart, I. Urban sprawl and climate change: a statistical exploration of cause and effect, with policy options for the EU. Land Use Policy 27 (2), 283–292 (2010).

Feng, H., Zou, B. & Tang, Y. M. Scale- and region-dependence in landscape-PM 2.5 correlation: implications for urban planning. Remote Sens. 9 , 918. https://doi.org/10.3390/rs9090918 (2017).

Rodríguez, M. C., Dupont-Courtade, L. & Oueslati, W. Air pollution and urban structure linkages: evidence from European cities. Renew. Sustain. Energy Rev. 53 , 1–9 (2016).

Bechle, M. J., Millet, D. B. & Marshall, J. D. Effects of income and urban form on urban NO2: global evidence from satellites. Environ. Sci. Technol. 45 (11), 4914–4919 (2011).

Article   ADS   CAS   PubMed   Google Scholar  

Martins, H., Miranda, A. & Borrego, C. Urban structure and air quality. In Air Pollution-A Comprehensive Perspective (2012).

Stone, B. Jr. Urban sprawl and air quality in large US cities. J. Environ. Manag. 86 (4), 688–698 (2008).

Breheny, M. Densities and sustainable cities: the UK experience. In Cities for the new millennium , 39–51 (2001).

Glaeser, E. L. & Kahn, M. E. Sprawl and urban growth. In Handbook of regional and urban economics , vol. 4, 2481–2527 (Elsevier, Amsterdam, 2004).

Manins, P. C. et al. The impact of urban development on air quality and energy use. Clean Air 18 , 21 (1998).

Troy, P. N. Environmental stress and urban policy. The compact city: a sustainable urban form, 200–211 (1996).

Gaigné, C., Riou, S. & Thisse, J. F. Are compact cities environmentally friendly?. J. Urban Econ. 72 (2–3), 123–136 (2012).

Wood, C. Air pollution control by land use planning techniques: a British-American review. Int. J. Environ. Stud. 35 (4), 233–243 (1990).

Zhou, B., Rybski, D. & Kropp, J. P. The role of city size and urban form in the surface urban heat island. Sci. Rep. 7 (1), 4791 (2017).

Sarrat, C., Lemonsu, A., Masson, V. & Guedalia, D. Impact of urban heat island on regional atmospheric pollution. Atmos. Environ. 40 (10), 1743–1758 (2006).

Article   ADS   CAS   Google Scholar  

Liu, Y., Wu, J., Yu, D. & Ma, Q. The relationship between urban form and air pollution depends on seasonality and city size. Environ. Sci. Pollut. Res. 25 (16), 15554–15567 (2018).

Cavalcante, R. M. et al. Influence of urbanization on air quality based on the occurrence of particle-associated polycyclic aromatic hydrocarbons in a tropical semiarid area (Fortaleza-CE, Brazil). Air Qual. Atmos. Health. 10 (4), 437–445 (2017).

Han, L., Zhou, W. & Li, W. Fine particulate (PM 2.5 ) dynamics during rapid urbanization in Beijing, 1973–2013. Sci. Rep. 6 , 23604 (2016).

Article   ADS   CAS   PubMed   PubMed Central   Google Scholar  

Tuo, Y., Li, X. & Wang, J. Negative effects of Beijing’s air pollution caused by urbanization on residents’ health. In 2nd International Conference on Science and Social Research (ICSSR 2013) , 732–735 (Atlantis Press, 2013).

Zhou, C. S., Li, S. J. & Wang, S. J. Examining the impacts of urban form on air pollution in developing countries: a case study of China’s megacities. Int. J. Environ. Res. Public Health. 15 (8), 1565 (2018).

Article   PubMed Central   CAS   Google Scholar  

Cariolet, J. M., Colombert, M., Vuillet, M. & Diab, Y. Assessing the resilience of urban areas to traffic-related air pollution: application in Greater Paris. Sci. Total Environ. 615 , 588–596 (2018).

She, Q. et al. Air quality and its response to satellite-derived urban form in the Yangtze River Delta, China. Ecol. Indic. 75 , 297–306 (2017).

Yang, D. et al. Global distribution and evolvement of urbanization and PM 2.5 (1998–2015). Atmos. Environ. 182 , 171–178 (2018).

Cho, H. S. & Choi, M. Effects of compact urban development on air pollution: empirical evidence from Korea. Sustainability 6 (9), 5968–5982 (2014).

Li, C., Wang, Z., Li, B., Peng, Z. R. & Fu, Q. Investigating the relationship between air pollution variation and urban form. Build. Environ. 147 , 559–568 (2019).

Montgomery, M. R. The urban transformation of the developing world. Science 319 (5864), 761–764 (2008).

United Nations. World Urbanization Prospects: The 2009 Revision (United Nations Publication, New York, 2010).

Jiang, L. & O’Neill, B. C. Global urbanization projections for the shared socioeconomic pathways. Glob. Environ. Change 42 , 193–199 (2017).

Martine, G., McGranahan, G., Montgomery, M. & Fernandez-Castilla, R. The New Global Frontier: Urbanization, Poverty and Environment in the 21st Century (Earthscan, London, 2008).

Gong, P., Li, X. C. & Zhang, W. 40-Year (1978–2017) human settlement changes in China reflected by impervious surfaces from satellite remote sensing. Sci. Bull. 64 (11), 756–763 (2019).

Center for International Earth Science Information Network—CIESIN—Columbia University, C. I.-C.-I.. Global Rural–Urban Mapping Project, Version 1 (GRUMPv1): Urban Extent Polygons, Revision 01 . Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC) (2017). https://doi.org/10.7927/H4Z31WKF . Accessed 10 April 2020.

Balk, D. L. et al. Determining global population distribution: methods, applications and data. Adv Parasit. 62 , 119–156. https://doi.org/10.1016/S0065-308X(05)62004-0 (2006).

Chinese Academy of Surveying and Mapping—CASM China in Time and Space—CITAS—University of Washington, a. C.-C. (1996). China Dimensions Data Collection: China Administrative Regions GIS Data: 1:1M, County Level, 1 July 1990 . Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC). https://doi.org/10.7927/H4GT5K3V . Accessed 10 April 2020.

Ma, L. J. Urban administrative restructuring, changing scale relations and local economic development in China. Polit. Geogr. 24 (4), 477–497 (2005).

Article   MathSciNet   Google Scholar  

Van Donkelaar, A. et al. Global estimates of fine particulate matter using a combined geophysical-statistical method with information from satellites, models, and monitors. Environ. Sci. Technol. 50 (7), 3762–3772 (2016).

Article   ADS   PubMed   CAS   Google Scholar  

Gong, P. et al. Annual maps of global artificial impervious area (GAIA) between 1985 and 2018. Remote Sens. Environ 236 , 111510 (2020).

Article   ADS   Google Scholar  

Li, X. C., Gong, P. & Liang, L. A 30-year (1984–2013) record of annual urban dynamics of Beijing City derived from Landsat data. Remote Sens. Environ. 166 , 78–90 (2015).

Li, X. C. & Gong, P. An, “exclusion-inclusion” framework for extracting human settlements in rapidly developing regions of China from Landsat images. Remote Sens. Environ. 186 , 286–296 (2016).

National Bureau of Statistics 2000–2014. China City Statistical Yearbook (China Statistics Press). ISBN: 978-7-5037-6387-8

Lai, A. C., Thatcher, T. L. & Nazaroff, W. W. Inhalation transfer factors for air pollution health risk assessment. J. Air Waste Manag. Assoc. 50 (9), 1688–1699 (2000).

Article   CAS   PubMed   Google Scholar  

Luo, Y. et al. Relationship between air pollutants and economic development of the provincial capital cities in China during the past decade. PLoS ONE 9 (8), e104013 (2014).

Hart, R., Liang, L. & Dong, P. Monitoring, mapping, and modeling spatial–temporal patterns of PM2.5 for improved understanding of air pollution dynamics using portable sensing technologies. Int. J. Environ. Res. Public Health 17 (14), 4914 (2020).

Wang, X. & Zhang, R. Effects of atmospheric circulations on the interannual variation in PM2.5 concentrations over the Beijing–Tianjin–Hebei region in 2013–2018. Atmos. Chem. Phys. 20 (13), 7667–7682 (2020).

Xu, Y. et al. Impact of meteorological conditions on PM 2.5 pollution in China during winter. Atmosphere 9 (11), 429 (2018).

Hernandez, G., Berry, T.A., Wallis, S. & Poyner, D. Temperature and humidity effects on particulate matter concentrations in a sub-tropical climate during winter. In Proceedings of the International Conference of the Environment, Chemistry and Biology (ICECB 2017), Queensland, Australia, 20–22 November 2017; Juan, L., Ed.; IRCSIT Press: Singapore, 2017.

Zhang, Y. Dynamic effect analysis of meteorological conditions on air pollution: a case study from Beijing. Sci. Total. Environ. 684 , 178–185 (2019).

National Earth System Science Data Center. National Science & Technology Infrastructure of China . https://www.geodata.cn . Accessed 6 Oct 2020.

Bhatta, B., Saraswati, S. & Bandyopadhyay, D. Urban sprawl measurement from remote sensing data. Appl. Geogr. 30 (4), 731–740 (2010).

Dietzel, C., Oguz, H., Hemphill, J. J., Clarke, K. C. & Gazulis, N. Diffusion and coalescence of the Houston Metropolitan Area: evidence supporting a new urban theory. Environ. Plan. B Plan. Des. 32 (2), 231–246 (2005).

Li, S., Zhou, C., Wang, S. & Hu, J. Dose urban landscape pattern affect CO2 emission efficiency? Empirical evidence from megacities in China. J. Clean. Prod. 203 , 164–178 (2018).

Gyenizse, P., Bognár, Z., Czigány, S. & Elekes, T. Landscape shape index, as a potencial indicator of urban development in Hungary. Acta Geogr. Debrecina Landsc. Environ. 8 (2), 78–88 (2014).

Rutledge, D. T. Landscape indices as measures of the effects of fragmentation: can pattern reflect process? DOC Science Internal Series . ISBN 0-478-22380-3 (2003).

Mcgarigal, K. & Marks, B. J. Spatial pattern analysis program for quantifying landscape structure. Gen. Tech. Rep. PNW-GTR-351. US Department of Agriculture, Forest Service, Pacific Northwest Research Station, 1–122 (1995).

Chan, C. K. & Yao, X. Air pollution in mega cities in China. Atmos. Environ. 42 (1), 1–42 (2008).

Anselin, L. The Moran Scatterplot as an ESDA Tool to Assess Local Instability in Spatial Association. In Spatial Analytical Perspectives on Gis in Environmental and Socio-Economic Sciences (eds Fischer, M. et al. ) 111–125 (Taylor; Francis, London, 1996).

Zou, B., Peng, F., Wan, N., Mamady, K. & Wilson, G. J. Spatial cluster detection of air pollution exposure inequities across the United States. PLoS ONE 9 (3), e91917 (2014).

Bone, C., Wulder, M. A., White, J. C., Robertson, C. & Nelson, T. A. A GIS-based risk rating of forest insect outbreaks using aerial overview surveys and the local Moran’s I statistic. Appl. Geogr. 40 , 161–170 (2013).

Anselin, L., Syabri, I. & Kho, Y. GeoDa: an introduction to spatial data analysis. Geogr. Anal. 38 , 5–22 (2006).

R Core Team. R A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, Vienna, 2013).

Cole, M. A. & Neumayer, E. Examining the impact of demographic factors on air pollution. Popul. Environ. 26 (1), 5–21 (2004).

Liu, Y., Arp, H. P. H., Song, X. & Song, Y. Research on the relationship between urban form and urban smog in China. Environ. Plan. B Urban Anal. City Sci. 44 (2), 328–342 (2017).

York, R., Rosa, E. A. & Dietz, T. STIRPAT, IPAT and ImPACT: analytic tools for unpacking the driving forces of environmental impacts. Ecol. Econ. 46 (3), 351–365 (2003).

United Nations, Department of Economic and Social Affairs Population Division 2011: the 2010 Revision (United Nations Publications, New York, 2011)

Ahn, S. C. & Schmidt, P. Efficient estimation of models for dynamic panel data. J. Econ. 68 (1), 5–27 (1995).

Article   MathSciNet   MATH   Google Scholar  

Du, L., Wei, C. & Cai, S. Economic development and carbon dioxide emissions in China: provincial panel data analysis. China Econ. Rev. 23 (2), 371–384 (2012).

Hausman, J. A. Specification tests in econometrics. Econ. J. Econ. Soc. 46 (6), 1251–1271 (1978).

Greene, W. H. Econometric Analysis (Pearson Education India, New Delhi, 2003).

ArcGIS GIS 10.7.1. (Environmental Systems Research Institute, Inc., Redlands, 2010).

Lao, X., Shen, T. & Gu, H. Prospect on China’s urban system by 2020: evidence from the prediction based on internal migration network. Sustainability 10 (3), 654 (2018).

Henderson, J.V., Logan, J.R. & Choi, S. Growth of China's medium-size cities . Brookings-Wharton Papers on Urban Affairs, 263–303 (2005).

Lu, H., Zhang, C., Liu, G., Ye, X. & Miao, C. Mapping China’s ghost cities through the combination of nighttime satellite data and daytime satellite data. Remote Sens. 10 (7), 1037 (2018).

Frank, L. D. et al. Many pathways from land use to health: associations between neighborhood walkability and active transportation, body mass index, and air quality. JAPA. 72 (1), 75–87 (2006).

Huo, H. & Wang, M. Modeling future vehicle sales and stock in China. Energy Policy 43 , 17–29 (2012).

Download references

Acknowledgements

Lu Liang received intramural research funding support from the UNT Office of Research and Innovation. Peng Gong is partially supported by the National Research Program of the Ministry of Science and Technology of the People’s Republic of China (2016YFA0600104), and donations from Delos Living LLC and the Cyrus Tang Foundation to Tsinghua University.

Author information

Authors and affiliations.

Department of Geography and the Environment, University of North Texas, 1155 Union Circle, Denton, TX, 76203, USA

Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China

Tsinghua Urban Institute, Tsinghua University, Beijing, 100084, China

Center for Healthy Cities, Institute for China Sustainable Urbanization, Tsinghua University, Beijing, 100084, China

You can also search for this author in PubMed   Google Scholar

Contributions

L.L. and P.G. wrote the main manuscript text. All authors reviewed the manuscript.

Corresponding author

Correspondence to Lu Liang .

Ethics declarations

Competing interests.

The authors declare no competing interests.

Additional information

Publisher's note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .

Reprints and permissions

About this article

Cite this article.

Liang, L., Gong, P. Urban and air pollution: a multi-city study of long-term effects of urban landscape patterns on air quality trends. Sci Rep 10 , 18618 (2020). https://doi.org/10.1038/s41598-020-74524-9

Download citation

Received : 11 June 2020

Accepted : 24 August 2020

Published : 29 October 2020

DOI : https://doi.org/10.1038/s41598-020-74524-9

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

This article is cited by

Spatial–temporal distribution patterns and influencing factors analysis of comorbidity prevalence of chronic diseases among middle-aged and elderly people in china: focusing on exposure to ambient fine particulate matter (pm2.5).

• Liangwen Zhang
• Linjiang Wei

BMC Public Health (2024)

The association between ambient air pollution exposure and connective tissue sarcoma risk: a nested case–control study using a nationwide population-based database

• Wei-Yi Huang
• Yu-Fen Chen
• Kuo-Yuan Huang

Environmental Science and Pollution Research (2024)

Systematic review of ecological research in Philippine cities: assessing the present status and charting future directions

• Anne Olfato-Parojinog
• Nikki Heherson A. Dagamac

Discover Environment (2024)

The evolution of atmospheric particulate matter in an urban landscape since the Industrial Revolution

• Ann L. Power
• Richard K. Tennant

Scientific Reports (2023)

Simulation of particle resuspension by wind in an urban system

• Amir Banari
• Daniel Hertel
• Gregory Lecrivain

Environmental Fluid Mechanics (2023)

By submitting a comment you agree to abide by our Terms and Community Guidelines . If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Sign up for the Nature Briefing: Anthropocene newsletter — what matters in anthropocene research, free to your inbox weekly.

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• Front Public Health

Environmental and Health Impacts of Air Pollution: A Review

Ioannis manisalidis.

1 Delphis S.A., Kifisia, Greece

2 Laboratory of Hygiene and Environmental Protection, Faculty of Medicine, Democritus University of Thrace, Alexandroupolis, Greece

Elisavet Stavropoulou

3 Centre Hospitalier Universitaire Vaudois (CHUV), Service de Médicine Interne, Lausanne, Switzerland

Agathangelos Stavropoulos

4 School of Social and Political Sciences, University of Glasgow, Glasgow, United Kingdom

Eugenia Bezirtzoglou

One of our era's greatest scourges is air pollution, on account not only of its impact on climate change but also its impact on public and individual health due to increasing morbidity and mortality. There are many pollutants that are major factors in disease in humans. Among them, Particulate Matter (PM), particles of variable but very small diameter, penetrate the respiratory system via inhalation, causing respiratory and cardiovascular diseases, reproductive and central nervous system dysfunctions, and cancer. Despite the fact that ozone in the stratosphere plays a protective role against ultraviolet irradiation, it is harmful when in high concentration at ground level, also affecting the respiratory and cardiovascular system. Furthermore, nitrogen oxide, sulfur dioxide, Volatile Organic Compounds (VOCs), dioxins, and polycyclic aromatic hydrocarbons (PAHs) are all considered air pollutants that are harmful to humans. Carbon monoxide can even provoke direct poisoning when breathed in at high levels. Heavy metals such as lead, when absorbed into the human body, can lead to direct poisoning or chronic intoxication, depending on exposure. Diseases occurring from the aforementioned substances include principally respiratory problems such as Chronic Obstructive Pulmonary Disease (COPD), asthma, bronchiolitis, and also lung cancer, cardiovascular events, central nervous system dysfunctions, and cutaneous diseases. Last but not least, climate change resulting from environmental pollution affects the geographical distribution of many infectious diseases, as do natural disasters. The only way to tackle this problem is through public awareness coupled with a multidisciplinary approach by scientific experts; national and international organizations must address the emergence of this threat and propose sustainable solutions.

Approach to the Problem

The interactions between humans and their physical surroundings have been extensively studied, as multiple human activities influence the environment. The environment is a coupling of the biotic (living organisms and microorganisms) and the abiotic (hydrosphere, lithosphere, and atmosphere).

Pollution is defined as the introduction into the environment of substances harmful to humans and other living organisms. Pollutants are harmful solids, liquids, or gases produced in higher than usual concentrations that reduce the quality of our environment.

Human activities have an adverse effect on the environment by polluting the water we drink, the air we breathe, and the soil in which plants grow. Although the industrial revolution was a great success in terms of technology, society, and the provision of multiple services, it also introduced the production of huge quantities of pollutants emitted into the air that are harmful to human health. Without any doubt, the global environmental pollution is considered an international public health issue with multiple facets. Social, economic, and legislative concerns and lifestyle habits are related to this major problem. Clearly, urbanization and industrialization are reaching unprecedented and upsetting proportions worldwide in our era. Anthropogenic air pollution is one of the biggest public health hazards worldwide, given that it accounts for about 9 million deaths per year ( 1 ).

Without a doubt, all of the aforementioned are closely associated with climate change, and in the event of danger, the consequences can be severe for mankind ( 2 ). Climate changes and the effects of global planetary warming seriously affect multiple ecosystems, causing problems such as food safety issues, ice and iceberg melting, animal extinction, and damage to plants ( 3 , 4 ).

Air pollution has various health effects. The health of susceptible and sensitive individuals can be impacted even on low air pollution days. Short-term exposure to air pollutants is closely related to COPD (Chronic Obstructive Pulmonary Disease), cough, shortness of breath, wheezing, asthma, respiratory disease, and high rates of hospitalization (a measurement of morbidity).

The long-term effects associated with air pollution are chronic asthma, pulmonary insufficiency, cardiovascular diseases, and cardiovascular mortality. According to a Swedish cohort study, diabetes seems to be induced after long-term air pollution exposure ( 5 ). Moreover, air pollution seems to have various malign health effects in early human life, such as respiratory, cardiovascular, mental, and perinatal disorders ( 3 ), leading to infant mortality or chronic disease in adult age ( 6 ).

National reports have mentioned the increased risk of morbidity and mortality ( 1 ). These studies were conducted in many places around the world and show a correlation between daily ranges of particulate matter (PM) concentration and daily mortality. Climate shifts and global planetary warming ( 3 ) could aggravate the situation. Besides, increased hospitalization (an index of morbidity) has been registered among the elderly and susceptible individuals for specific reasons. Fine and ultrafine particulate matter seems to be associated with more serious illnesses ( 6 ), as it can invade the deepest parts of the airways and more easily reach the bloodstream.

Air pollution mainly affects those living in large urban areas, where road emissions contribute the most to the degradation of air quality. There is also a danger of industrial accidents, where the spread of a toxic fog can be fatal to the populations of the surrounding areas. The dispersion of pollutants is determined by many parameters, most notably atmospheric stability and wind ( 6 ).

In developing countries ( 7 ), the problem is more serious due to overpopulation and uncontrolled urbanization along with the development of industrialization. This leads to poor air quality, especially in countries with social disparities and a lack of information on sustainable management of the environment. The use of fuels such as wood fuel or solid fuel for domestic needs due to low incomes exposes people to bad-quality, polluted air at home. It is of note that three billion people around the world are using the above sources of energy for their daily heating and cooking needs ( 8 ). In developing countries, the women of the household seem to carry the highest risk for disease development due to their longer duration exposure to the indoor air pollution ( 8 , 9 ). Due to its fast industrial development and overpopulation, China is one of the Asian countries confronting serious air pollution problems ( 10 , 11 ). The lung cancer mortality observed in China is associated with fine particles ( 12 ). As stated already, long-term exposure is associated with deleterious effects on the cardiovascular system ( 3 , 5 ). However, it is interesting to note that cardiovascular diseases have mostly been observed in developed and high-income countries rather than in the developing low-income countries exposed highly to air pollution ( 13 ). Extreme air pollution is recorded in India, where the air quality reaches hazardous levels. New Delhi is one of the more polluted cities in India. Flights in and out of New Delhi International Airport are often canceled due to the reduced visibility associated with air pollution. Pollution is occurring both in urban and rural areas in India due to the fast industrialization, urbanization, and rise in use of motorcycle transportation. Nevertheless, biomass combustion associated with heating and cooking needs and practices is a major source of household air pollution in India and in Nepal ( 14 , 15 ). There is spatial heterogeneity in India, as areas with diverse climatological conditions and population and education levels generate different indoor air qualities, with higher PM 2.5 observed in North Indian states (557–601 μg/m 3 ) compared to the Southern States (183–214 μg/m 3 ) ( 16 , 17 ). The cold climate of the North Indian areas may be the main reason for this, as longer periods at home and more heating are necessary compared to in the tropical climate of Southern India. Household air pollution in India is associated with major health effects, especially in women and young children, who stay indoors for longer periods. Chronic obstructive respiratory disease (CORD) and lung cancer are mostly observed in women, while acute lower respiratory disease is seen in young children under 5 years of age ( 18 ).

Accumulation of air pollution, especially sulfur dioxide and smoke, reaching 1,500 mg/m3, resulted in an increase in the number of deaths (4,000 deaths) in December 1952 in London and in 1963 in New York City (400 deaths) ( 19 ). An association of pollution with mortality was reported on the basis of monitoring of outdoor pollution in six US metropolitan cities ( 20 ). In every case, it seems that mortality was closely related to the levels of fine, inhalable, and sulfate particles more than with the levels of total particulate pollution, aerosol acidity, sulfur dioxide, or nitrogen dioxide ( 20 ).

Furthermore, extremely high levels of pollution are reported in Mexico City and Rio de Janeiro, followed by Milan, Ankara, Melbourne, Tokyo, and Moscow ( 19 ).

Based on the magnitude of the public health impact, it is certain that different kinds of interventions should be taken into account. Success and effectiveness in controlling air pollution, specifically at the local level, have been reported. Adequate technological means are applied considering the source and the nature of the emission as well as its impact on health and the environment. The importance of point sources and non-point sources of air pollution control is reported by Schwela and Köth-Jahr ( 21 ). Without a doubt, a detailed emission inventory must record all sources in a given area. Beyond considering the above sources and their nature, topography and meteorology should also be considered, as stated previously. Assessment of the control policies and methods is often extrapolated from the local to the regional and then to the global scale. Air pollution may be dispersed and transported from one region to another area located far away. Air pollution management means the reduction to acceptable levels or possible elimination of air pollutants whose presence in the air affects our health or the environmental ecosystem. Private and governmental entities and authorities implement actions to ensure the air quality ( 22 ). Air quality standards and guidelines were adopted for the different pollutants by the WHO and EPA as a tool for the management of air quality ( 1 , 23 ). These standards have to be compared to the emissions inventory standards by causal analysis and dispersion modeling in order to reveal the problematic areas ( 24 ). Inventories are generally based on a combination of direct measurements and emissions modeling ( 24 ).

As an example, we state here the control measures at the source through the use of catalytic converters in cars. These are devices that turn the pollutants and toxic gases produced from combustion engines into less-toxic pollutants by catalysis through redox reactions ( 25 ). In Greece, the use of private cars was restricted by tracking their license plates in order to reduce traffic congestion during rush hour ( 25 ).

Concerning industrial emissions, collectors and closed systems can keep the air pollution to the minimal standards imposed by legislation ( 26 ).

Current strategies to improve air quality require an estimation of the economic value of the benefits gained from proposed programs. These proposed programs by public authorities, and directives are issued with guidelines to be respected.

In Europe, air quality limit values AQLVs (Air Quality Limit Values) are issued for setting off planning claims ( 27 ). In the USA, the NAAQS (National Ambient Air Quality Standards) establish the national air quality limit values ( 27 ). While both standards and directives are based on different mechanisms, significant success has been achieved in the reduction of overall emissions and associated health and environmental effects ( 27 ). The European Directive identifies geographical areas of risk exposure as monitoring/assessment zones to record the emission sources and levels of air pollution ( 27 ), whereas the USA establishes global geographical air quality criteria according to the severity of their air quality problem and records all sources of the pollutants and their precursors ( 27 ).

In this vein, funds have been financing, directly or indirectly, projects related to air quality along with the technical infrastructure to maintain good air quality. These plans focus on an inventory of databases from air quality environmental planning awareness campaigns. Moreover, pollution measures of air emissions may be taken for vehicles, machines, and industries in urban areas.

Technological innovation can only be successful if it is able to meet the needs of society. In this sense, technology must reflect the decision-making practices and procedures of those involved in risk assessment and evaluation and act as a facilitator in providing information and assessments to enable decision makers to make the best decisions possible. Summarizing the aforementioned in order to design an effective air quality control strategy, several aspects must be considered: environmental factors and ambient air quality conditions, engineering factors and air pollutant characteristics, and finally, economic operating costs for technological improvement and administrative and legal costs. Considering the economic factor, competitiveness through neoliberal concepts is offering a solution to environmental problems ( 22 ).

The development of environmental governance, along with technological progress, has initiated the deployment of a dialogue. Environmental politics has created objections and points of opposition between different political parties, scientists, media, and governmental and non-governmental organizations ( 22 ). Radical environmental activism actions and movements have been created ( 22 ). The rise of the new information and communication technologies (ICTs) are many times examined as to whether and in which way they have influenced means of communication and social movements such as activism ( 28 ). Since the 1990s, the term “digital activism” has been used increasingly and in many different disciplines ( 29 ). Nowadays, multiple digital technologies can be used to produce a digital activism outcome on environmental issues. More specifically, devices with online capabilities such as computers or mobile phones are being used as a way to pursue change in political and social affairs ( 30 ).

In the present paper, we focus on the sources of environmental pollution in relation to public health and propose some solutions and interventions that may be of interest to environmental legislators and decision makers.

Sources of Exposure

It is known that the majority of environmental pollutants are emitted through large-scale human activities such as the use of industrial machinery, power-producing stations, combustion engines, and cars. Because these activities are performed at such a large scale, they are by far the major contributors to air pollution, with cars estimated to be responsible for approximately 80% of today's pollution ( 31 ). Some other human activities are also influencing our environment to a lesser extent, such as field cultivation techniques, gas stations, fuel tanks heaters, and cleaning procedures ( 32 ), as well as several natural sources, such as volcanic and soil eruptions and forest fires.

The classification of air pollutants is based mainly on the sources producing pollution. Therefore, it is worth mentioning the four main sources, following the classification system: Major sources, Area sources, Mobile sources, and Natural sources.

Major sources include the emission of pollutants from power stations, refineries, and petrochemicals, the chemical and fertilizer industries, metallurgical and other industrial plants, and, finally, municipal incineration.

Indoor area sources include domestic cleaning activities, dry cleaners, printing shops, and petrol stations.

Mobile sources include automobiles, cars, railways, airways, and other types of vehicles.

Finally, natural sources include, as stated previously, physical disasters ( 33 ) such as forest fire, volcanic erosion, dust storms, and agricultural burning.

However, many classification systems have been proposed. Another type of classification is a grouping according to the recipient of the pollution, as follows:

Air pollution is determined as the presence of pollutants in the air in large quantities for long periods. Air pollutants are dispersed particles, hydrocarbons, CO, CO 2 , NO, NO 2 , SO 3 , etc.

Water pollution is organic and inorganic charge and biological charge ( 10 ) at high levels that affect the water quality ( 34 , 35 ).

Soil pollution occurs through the release of chemicals or the disposal of wastes, such as heavy metals, hydrocarbons, and pesticides.

Air pollution can influence the quality of soil and water bodies by polluting precipitation, falling into water and soil environments ( 34 , 36 ). Notably, the chemistry of the soil can be amended due to acid precipitation by affecting plants, cultures, and water quality ( 37 ). Moreover, movement of heavy metals is favored by soil acidity, and metals are so then moving into the watery environment. It is known that heavy metals such as aluminum are noxious to wildlife and fishes. Soil quality seems to be of importance, as soils with low calcium carbonate levels are at increased jeopardy from acid rain. Over and above rain, snow and particulate matter drip into watery ' bodies ( 36 , 38 ).

Lastly, pollution is classified following type of origin:

Radioactive and nuclear pollution , releasing radioactive and nuclear pollutants into water, air, and soil during nuclear explosions and accidents, from nuclear weapons, and through handling or disposal of radioactive sewage.

Radioactive materials can contaminate surface water bodies and, being noxious to the environment, plants, animals, and humans. It is known that several radioactive substances such as radium and uranium concentrate in the bones and can cause cancers ( 38 , 39 ).

Noise pollution is produced by machines, vehicles, traffic noises, and musical installations that are harmful to our hearing.

The World Health Organization introduced the term DALYs. The DALYs for a disease or health condition is defined as the sum of the Years of Life Lost (YLL) due to premature mortality in the population and the Years Lost due to Disability (YLD) for people living with the health condition or its consequences ( 39 ). In Europe, air pollution is the main cause of disability-adjusted life years lost (DALYs), followed by noise pollution. The potential relationships of noise and air pollution with health have been studied ( 40 ). The study found that DALYs related to noise were more important than those related to air pollution, as the effects of environmental noise on cardiovascular disease were independent of air pollution ( 40 ). Environmental noise should be counted as an independent public health risk ( 40 ).

Environmental pollution occurs when changes in the physical, chemical, or biological constituents of the environment (air masses, temperature, climate, etc.) are produced.

Pollutants harm our environment either by increasing levels above normal or by introducing harmful toxic substances. Primary pollutants are directly produced from the above sources, and secondary pollutants are emitted as by-products of the primary ones. Pollutants can be biodegradable or non-biodegradable and of natural origin or anthropogenic, as stated previously. Moreover, their origin can be a unique source (point-source) or dispersed sources.

Pollutants have differences in physical and chemical properties, explaining the discrepancy in their capacity for producing toxic effects. As an example, we state here that aerosol compounds ( 41 – 43 ) have a greater toxicity than gaseous compounds due to their tiny size (solid or liquid) in the atmosphere; they have a greater penetration capacity. Gaseous compounds are eliminated more easily by our respiratory system ( 41 ). These particles are able to damage lungs and can even enter the bloodstream ( 41 ), leading to the premature deaths of millions of people yearly. Moreover, the aerosol acidity ([H+]) seems to considerably enhance the production of secondary organic aerosols (SOA), but this last aspect is not supported by other scientific teams ( 38 ).

Climate and Pollution

Air pollution and climate change are closely related. Climate is the other side of the same coin that reduces the quality of our Earth ( 44 ). Pollutants such as black carbon, methane, tropospheric ozone, and aerosols affect the amount of incoming sunlight. As a result, the temperature of the Earth is increasing, resulting in the melting of ice, icebergs, and glaciers.

In this vein, climatic changes will affect the incidence and prevalence of both residual and imported infections in Europe. Climate and weather affect the duration, timing, and intensity of outbreaks strongly and change the map of infectious diseases in the globe ( 45 ). Mosquito-transmitted parasitic or viral diseases are extremely climate-sensitive, as warming firstly shortens the pathogen incubation period and secondly shifts the geographic map of the vector. Similarly, water-warming following climate changes leads to a high incidence of waterborne infections. Recently, in Europe, eradicated diseases seem to be emerging due to the migration of population, for example, cholera, poliomyelitis, tick-borne encephalitis, and malaria ( 46 ).

The spread of epidemics is associated with natural climate disasters and storms, which seem to occur more frequently nowadays ( 47 ). Malnutrition and disequilibration of the immune system are also associated with the emerging infections affecting public health ( 48 ).

The Chikungunya virus “took the airplane” from the Indian Ocean to Europe, as outbreaks of the disease were registered in Italy ( 49 ) as well as autochthonous cases in France ( 50 ).

An increase in cryptosporidiosis in the United Kingdom and in the Czech Republic seems to have occurred following flooding ( 36 , 51 ).

As stated previously, aerosols compounds are tiny in size and considerably affect the climate. They are able to dissipate sunlight (the albedo phenomenon) by dispersing a quarter of the sun's rays back to space and have cooled the global temperature over the last 30 years ( 52 ).

Air Pollutants

The World Health Organization (WHO) reports on six major air pollutants, namely particle pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Air pollution can have a disastrous effect on all components of the environment, including groundwater, soil, and air. Additionally, it poses a serious threat to living organisms. In this vein, our interest is mainly to focus on these pollutants, as they are related to more extensive and severe problems in human health and environmental impact. Acid rain, global warming, the greenhouse effect, and climate changes have an important ecological impact on air pollution ( 53 ).

Particulate Matter (PM) and Health

Studies have shown a relationship between particulate matter (PM) and adverse health effects, focusing on either short-term (acute) or long-term (chronic) PM exposure.

Particulate matter (PM) is usually formed in the atmosphere as a result of chemical reactions between the different pollutants. The penetration of particles is closely dependent on their size ( 53 ). Particulate Matter (PM) was defined as a term for particles by the United States Environmental Protection Agency ( 54 ). Particulate matter (PM) pollution includes particles with diameters of 10 micrometers (μm) or smaller, called PM 10 , and extremely fine particles with diameters that are generally 2.5 micrometers (μm) and smaller.

Particulate matter contains tiny liquid or solid droplets that can be inhaled and cause serious health effects ( 55 ). Particles <10 μm in diameter (PM 10 ) after inhalation can invade the lungs and even reach the bloodstream. Fine particles, PM 2.5 , pose a greater risk to health ( 6 , 56 ) ( Table 1 ).

Penetrability according to particle size.

Multiple epidemiological studies have been performed on the health effects of PM. A positive relation was shown between both short-term and long-term exposures of PM 2.5 and acute nasopharyngitis ( 56 ). In addition, long-term exposure to PM for years was found to be related to cardiovascular diseases and infant mortality.

Those studies depend on PM 2.5 monitors and are restricted in terms of study area or city area due to a lack of spatially resolved daily PM 2.5 concentration data and, in this way, are not representative of the entire population. Following a recent epidemiological study by the Department of Environmental Health at Harvard School of Public Health (Boston, MA) ( 57 ), it was reported that, as PM 2.5 concentrations vary spatially, an exposure error (Berkson error) seems to be produced, and the relative magnitudes of the short- and long-term effects are not yet completely elucidated. The team developed a PM 2.5 exposure model based on remote sensing data for assessing short- and long-term human exposures ( 57 ). This model permits spatial resolution in short-term effects plus the assessment of long-term effects in the whole population.

Moreover, respiratory diseases and affection of the immune system are registered as long-term chronic effects ( 58 ). It is worth noting that people with asthma, pneumonia, diabetes, and respiratory and cardiovascular diseases are especially susceptible and vulnerable to the effects of PM. PM 2.5 , followed by PM 10 , are strongly associated with diverse respiratory system diseases ( 59 ), as their size permits them to pierce interior spaces ( 60 ). The particles produce toxic effects according to their chemical and physical properties. The components of PM 10 and PM 2.5 can be organic (polycyclic aromatic hydrocarbons, dioxins, benzene, 1-3 butadiene) or inorganic (carbon, chlorides, nitrates, sulfates, metals) in nature ( 55 ).

Particulate Matter (PM) is divided into four main categories according to type and size ( 61 ) ( Table 2 ).

Types and sizes of particulate Matter (PM).

Gas contaminants include PM in aerial masses.

Particulate contaminants include contaminants such as smog, soot, tobacco smoke, oil smoke, fly ash, and cement dust.

Biological Contaminants are microorganisms (bacteria, viruses, fungi, mold, and bacterial spores), cat allergens, house dust and allergens, and pollen.

Types of Dust include suspended atmospheric dust, settling dust, and heavy dust.

Finally, another fact is that the half-lives of PM 10 and PM 2.5 particles in the atmosphere is extended due to their tiny dimensions; this permits their long-lasting suspension in the atmosphere and even their transfer and spread to distant destinations where people and the environment may be exposed to the same magnitude of pollution ( 53 ). They are able to change the nutrient balance in watery ecosystems, damage forests and crops, and acidify water bodies.

As stated, PM 2.5 , due to their tiny size, are causing more serious health effects. These aforementioned fine particles are the main cause of the “haze” formation in different metropolitan areas ( 12 , 13 , 61 ).

Ozone Impact in the Atmosphere

Ozone (O 3 ) is a gas formed from oxygen under high voltage electric discharge ( 62 ). It is a strong oxidant, 52% stronger than chlorine. It arises in the stratosphere, but it could also arise following chain reactions of photochemical smog in the troposphere ( 63 ).

Ozone can travel to distant areas from its initial source, moving with air masses ( 64 ). It is surprising that ozone levels over cities are low in contrast to the increased amounts occuring in urban areas, which could become harmful for cultures, forests, and vegetation ( 65 ) as it is reducing carbon assimilation ( 66 ). Ozone reduces growth and yield ( 47 , 48 ) and affects the plant microflora due to its antimicrobial capacity ( 67 , 68 ). In this regard, ozone acts upon other natural ecosystems, with microflora ( 69 , 70 ) and animal species changing their species composition ( 71 ). Ozone increases DNA damage in epidermal keratinocytes and leads to impaired cellular function ( 72 ).

Ground-level ozone (GLO) is generated through a chemical reaction between oxides of nitrogen and VOCs emitted from natural sources and/or following anthropogenic activities.

Ozone uptake usually occurs by inhalation. Ozone affects the upper layers of the skin and the tear ducts ( 73 ). A study of short-term exposure of mice to high levels of ozone showed malondialdehyde formation in the upper skin (epidermis) but also depletion in vitamins C and E. It is likely that ozone levels are not interfering with the skin barrier function and integrity to predispose to skin disease ( 74 ).

Due to the low water-solubility of ozone, inhaled ozone has the capacity to penetrate deeply into the lungs ( 75 ).

Toxic effects induced by ozone are registered in urban areas all over the world, causing biochemical, morphologic, functional, and immunological disorders ( 76 ).

The European project (APHEA2) focuses on the acute effects of ambient ozone concentrations on mortality ( 77 ). Daily ozone concentrations compared to the daily number of deaths were reported from different European cities for a 3-year period. During the warm period of the year, an observed increase in ozone concentration was associated with an increase in the daily number of deaths (0.33%), in the number of respiratory deaths (1.13%), and in the number of cardiovascular deaths (0.45%). No effect was observed during wintertime.

Carbon Monoxide (CO)

Carbon monoxide is produced by fossil fuel when combustion is incomplete. The symptoms of poisoning due to inhaling carbon monoxide include headache, dizziness, weakness, nausea, vomiting, and, finally, loss of consciousness.

The affinity of carbon monoxide to hemoglobin is much greater than that of oxygen. In this vein, serious poisoning may occur in people exposed to high levels of carbon monoxide for a long period of time. Due to the loss of oxygen as a result of the competitive binding of carbon monoxide, hypoxia, ischemia, and cardiovascular disease are observed.

Carbon monoxide affects the greenhouses gases that are tightly connected to global warming and climate. This should lead to an increase in soil and water temperatures, and extreme weather conditions or storms may occur ( 68 ).

However, in laboratory and field experiments, it has been seen to produce increased plant growth ( 78 ).

Nitrogen Oxide (NO 2 )

Nitrogen oxide is a traffic-related pollutant, as it is emitted from automobile motor engines ( 79 , 80 ). It is an irritant of the respiratory system as it penetrates deep in the lung, inducing respiratory diseases, coughing, wheezing, dyspnea, bronchospasm, and even pulmonary edema when inhaled at high levels. It seems that concentrations over 0.2 ppm produce these adverse effects in humans, while concentrations higher than 2.0 ppm affect T-lymphocytes, particularly the CD8+ cells and NK cells that produce our immune response ( 81 ).It is reported that long-term exposure to high levels of nitrogen dioxide can be responsible for chronic lung disease. Long-term exposure to NO 2 can impair the sense of smell ( 81 ).

However, systems other than respiratory ones can be involved, as symptoms such as eye, throat, and nose irritation have been registered ( 81 ).

High levels of nitrogen dioxide are deleterious to crops and vegetation, as they have been observed to reduce crop yield and plant growth efficiency. Moreover, NO 2 can reduce visibility and discolor fabrics ( 81 ).

Sulfur Dioxide (SO 2 )

Sulfur dioxide is a harmful gas that is emitted mainly from fossil fuel consumption or industrial activities. The annual standard for SO 2 is 0.03 ppm ( 82 ). It affects human, animal, and plant life. Susceptible people as those with lung disease, old people, and children, who present a higher risk of damage. The major health problems associated with sulfur dioxide emissions in industrialized areas are respiratory irritation, bronchitis, mucus production, and bronchospasm, as it is a sensory irritant and penetrates deep into the lung converted into bisulfite and interacting with sensory receptors, causing bronchoconstriction. Moreover, skin redness, damage to the eyes (lacrimation and corneal opacity) and mucous membranes, and worsening of pre-existing cardiovascular disease have been observed ( 81 ).

Environmental adverse effects, such as acidification of soil and acid rain, seem to be associated with sulfur dioxide emissions ( 83 ).

Lead is a heavy metal used in different industrial plants and emitted from some petrol motor engines, batteries, radiators, waste incinerators, and waste waters ( 84 ).

Moreover, major sources of lead pollution in the air are metals, ore, and piston-engine aircraft. Lead poisoning is a threat to public health due to its deleterious effects upon humans, animals, and the environment, especially in the developing countries.

Exposure to lead can occur through inhalation, ingestion, and dermal absorption. Trans- placental transport of lead was also reported, as lead passes through the placenta unencumbered ( 85 ). The younger the fetus is, the more harmful the toxic effects. Lead toxicity affects the fetal nervous system; edema or swelling of the brain is observed ( 86 ). Lead, when inhaled, accumulates in the blood, soft tissue, liver, lung, bones, and cardiovascular, nervous, and reproductive systems. Moreover, loss of concentration and memory, as well as muscle and joint pain, were observed in adults ( 85 , 86 ).

Children and newborns ( 87 ) are extremely susceptible even to minimal doses of lead, as it is a neurotoxicant and causes learning disabilities, impairment of memory, hyperactivity, and even mental retardation.

Elevated amounts of lead in the environment are harmful to plants and crop growth. Neurological effects are observed in vertebrates and animals in association with high lead levels ( 88 ).

Polycyclic Aromatic Hydrocarbons(PAHs)

The distribution of PAHs is ubiquitous in the environment, as the atmosphere is the most important means of their dispersal. They are found in coal and in tar sediments. Moreover, they are generated through incomplete combustion of organic matter as in the cases of forest fires, incineration, and engines ( 89 ). PAH compounds, such as benzopyrene, acenaphthylene, anthracene, and fluoranthene are recognized as toxic, mutagenic, and carcinogenic substances. They are an important risk factor for lung cancer ( 89 ).

Volatile Organic Compounds(VOCs)

Volatile organic compounds (VOCs), such as toluene, benzene, ethylbenzene, and xylene ( 90 ), have been found to be associated with cancer in humans ( 91 ). The use of new products and materials has actually resulted in increased concentrations of VOCs. VOCs pollute indoor air ( 90 ) and may have adverse effects on human health ( 91 ). Short-term and long-term adverse effects on human health are observed. VOCs are responsible for indoor air smells. Short-term exposure is found to cause irritation of eyes, nose, throat, and mucosal membranes, while those of long duration exposure include toxic reactions ( 92 ). Predictable assessment of the toxic effects of complex VOC mixtures is difficult to estimate, as these pollutants can have synergic, antagonistic, or indifferent effects ( 91 , 93 ).

Dioxins originate from industrial processes but also come from natural processes, such as forest fires and volcanic eruptions. They accumulate in foods such as meat and dairy products, fish and shellfish, and especially in the fatty tissue of animals ( 94 ).

Short-period exhibition to high dioxin concentrations may result in dark spots and lesions on the skin ( 94 ). Long-term exposure to dioxins can cause developmental problems, impairment of the immune, endocrine and nervous systems, reproductive infertility, and cancer ( 94 ).

Without any doubt, fossil fuel consumption is responsible for a sizeable part of air contamination. This contamination may be anthropogenic, as in agricultural and industrial processes or transportation, while contamination from natural sources is also possible. Interestingly, it is of note that the air quality standards established through the European Air Quality Directive are somewhat looser than the WHO guidelines, which are stricter ( 95 ).

Effect of Air Pollution on Health

The most common air pollutants are ground-level ozone and Particulates Matter (PM). Air pollution is distinguished into two main types:

Outdoor pollution is the ambient air pollution.

Indoor pollution is the pollution generated by household combustion of fuels.

People exposed to high concentrations of air pollutants experience disease symptoms and states of greater and lesser seriousness. These effects are grouped into short- and long-term effects affecting health.

Susceptible populations that need to be aware of health protection measures include old people, children, and people with diabetes and predisposing heart or lung disease, especially asthma.

As extensively stated previously, according to a recent epidemiological study from Harvard School of Public Health, the relative magnitudes of the short- and long-term effects have not been completely clarified ( 57 ) due to the different epidemiological methodologies and to the exposure errors. New models are proposed for assessing short- and long-term human exposure data more successfully ( 57 ). Thus, in the present section, we report the more common short- and long-term health effects but also general concerns for both types of effects, as these effects are often dependent on environmental conditions, dose, and individual susceptibility.

Short-term effects are temporary and range from simple discomfort, such as irritation of the eyes, nose, skin, throat, wheezing, coughing and chest tightness, and breathing difficulties, to more serious states, such as asthma, pneumonia, bronchitis, and lung and heart problems. Short-term exposure to air pollution can also cause headaches, nausea, and dizziness.

These problems can be aggravated by extended long-term exposure to the pollutants, which is harmful to the neurological, reproductive, and respiratory systems and causes cancer and even, rarely, deaths.

The long-term effects are chronic, lasting for years or the whole life and can even lead to death. Furthermore, the toxicity of several air pollutants may also induce a variety of cancers in the long term ( 96 ).

As stated already, respiratory disorders are closely associated with the inhalation of air pollutants. These pollutants will invade through the airways and will accumulate at the cells. Damage to target cells should be related to the pollutant component involved and its source and dose. Health effects are also closely dependent on country, area, season, and time. An extended exposure duration to the pollutant should incline to long-term health effects in relation also to the above factors.

Particulate Matter (PMs), dust, benzene, and O 3 cause serious damage to the respiratory system ( 97 ). Moreover, there is a supplementary risk in case of existing respiratory disease such as asthma ( 98 ). Long-term effects are more frequent in people with a predisposing disease state. When the trachea is contaminated by pollutants, voice alterations may be remarked after acute exposure. Chronic obstructive pulmonary disease (COPD) may be induced following air pollution, increasing morbidity and mortality ( 99 ). Long-term effects from traffic, industrial air pollution, and combustion of fuels are the major factors for COPD risk ( 99 ).

Multiple cardiovascular effects have been observed after exposure to air pollutants ( 100 ). Changes occurred in blood cells after long-term exposure may affect cardiac functionality. Coronary arteriosclerosis was reported following long-term exposure to traffic emissions ( 101 ), while short-term exposure is related to hypertension, stroke, myocardial infracts, and heart insufficiency. Ventricle hypertrophy is reported to occur in humans after long-time exposure to nitrogen oxide (NO 2 ) ( 102 , 103 ).

Neurological effects have been observed in adults and children after extended-term exposure to air pollutants.

Psychological complications, autism, retinopathy, fetal growth, and low birth weight seem to be related to long-term air pollution ( 83 ). The etiologic agent of the neurodegenerative diseases (Alzheimer's and Parkinson's) is not yet known, although it is believed that extended exposure to air pollution seems to be a factor. Specifically, pesticides and metals are cited as etiological factors, together with diet. The mechanisms in the development of neurodegenerative disease include oxidative stress, protein aggregation, inflammation, and mitochondrial impairment in neurons ( 104 ) ( Figure 1 ).

Impact of air pollutants on the brain.

Brain inflammation was observed in dogs living in a highly polluted area in Mexico for a long period ( 105 ). In human adults, markers of systemic inflammation (IL-6 and fibrinogen) were found to be increased as an immediate response to PNC on the IL-6 level, possibly leading to the production of acute-phase proteins ( 106 ). The progression of atherosclerosis and oxidative stress seem to be the mechanisms involved in the neurological disturbances caused by long-term air pollution. Inflammation comes secondary to the oxidative stress and seems to be involved in the impairment of developmental maturation, affecting multiple organs ( 105 , 107 ). Similarly, other factors seem to be involved in the developmental maturation, which define the vulnerability to long-term air pollution. These include birthweight, maternal smoking, genetic background and socioeconomic environment, as well as education level.

However, diet, starting from breast-feeding, is another determinant factor. Diet is the main source of antioxidants, which play a key role in our protection against air pollutants ( 108 ). Antioxidants are free radical scavengers and limit the interaction of free radicals in the brain ( 108 ). Similarly, genetic background may result in a differential susceptibility toward the oxidative stress pathway ( 60 ). For example, antioxidant supplementation with vitamins C and E appears to modulate the effect of ozone in asthmatic children homozygous for the GSTM1 null allele ( 61 ). Inflammatory cytokines released in the periphery (e.g., respiratory epithelia) upregulate the innate immune Toll-like receptor 2. Such activation and the subsequent events leading to neurodegeneration have recently been observed in lung lavage in mice exposed to ambient Los Angeles (CA, USA) particulate matter ( 61 ). In children, neurodevelopmental morbidities were observed after lead exposure. These children developed aggressive and delinquent behavior, reduced intelligence, learning difficulties, and hyperactivity ( 109 ). No level of lead exposure seems to be “safe,” and the scientific community has asked the Centers for Disease Control and Prevention (CDC) to reduce the current screening guideline of 10 μg/dl ( 109 ).

It is important to state that impact on the immune system, causing dysfunction and neuroinflammation ( 104 ), is related to poor air quality. Yet, increases in serum levels of immunoglobulins (IgA, IgM) and the complement component C3 are observed ( 106 ). Another issue is that antigen presentation is affected by air pollutants, as there is an upregulation of costimulatory molecules such as CD80 and CD86 on macrophages ( 110 ).

As is known, skin is our shield against ultraviolet radiation (UVR) and other pollutants, as it is the most exterior layer of our body. Traffic-related pollutants, such as PAHs, VOCs, oxides, and PM, may cause pigmented spots on our skin ( 111 ). On the one hand, as already stated, when pollutants penetrate through the skin or are inhaled, damage to the organs is observed, as some of these pollutants are mutagenic and carcinogenic, and, specifically, they affect the liver and lung. On the other hand, air pollutants (and those in the troposphere) reduce the adverse effects of ultraviolet radiation UVR in polluted urban areas ( 111 ). Air pollutants absorbed by the human skin may contribute to skin aging, psoriasis, acne, urticaria, eczema, and atopic dermatitis ( 111 ), usually caused by exposure to oxides and photochemical smoke ( 111 ). Exposure to PM and cigarette smoking act as skin-aging agents, causing spots, dyschromia, and wrinkles. Lastly, pollutants have been associated with skin cancer ( 111 ).

Higher morbidity is reported to fetuses and children when exposed to the above dangers. Impairment in fetal growth, low birth weight, and autism have been reported ( 112 ).

Another exterior organ that may be affected is the eye. Contamination usually comes from suspended pollutants and may result in asymptomatic eye outcomes, irritation ( 112 ), retinopathy, or dry eye syndrome ( 113 , 114 ).

Environmental Impact of Air Pollution

Air pollution is harming not only human health but also the environment ( 115 ) in which we live. The most important environmental effects are as follows.

Acid rain is wet (rain, fog, snow) or dry (particulates and gas) precipitation containing toxic amounts of nitric and sulfuric acids. They are able to acidify the water and soil environments, damage trees and plantations, and even damage buildings and outdoor sculptures, constructions, and statues.

Haze is produced when fine particles are dispersed in the air and reduce the transparency of the atmosphere. It is caused by gas emissions in the air coming from industrial facilities, power plants, automobiles, and trucks.

Ozone , as discussed previously, occurs both at ground level and in the upper level (stratosphere) of the Earth's atmosphere. Stratospheric ozone is protecting us from the Sun's harmful ultraviolet (UV) rays. In contrast, ground-level ozone is harmful to human health and is a pollutant. Unfortunately, stratospheric ozone is gradually damaged by ozone-depleting substances (i.e., chemicals, pesticides, and aerosols). If this protecting stratospheric ozone layer is thinned, then UV radiation can reach our Earth, with harmful effects for human life (skin cancer) ( 116 ) and crops ( 117 ). In plants, ozone penetrates through the stomata, inducing them to close, which blocks CO 2 transfer and induces a reduction in photosynthesis ( 118 ).

Global climate change is an important issue that concerns mankind. As is known, the “greenhouse effect” keeps the Earth's temperature stable. Unhappily, anthropogenic activities have destroyed this protecting temperature effect by producing large amounts of greenhouse gases, and global warming is mounting, with harmful effects on human health, animals, forests, wildlife, agriculture, and the water environment. A report states that global warming is adding to the health risks of poor people ( 119 ).

People living in poorly constructed buildings in warm-climate countries are at high risk for heat-related health problems as temperatures mount ( 119 ).

Wildlife is burdened by toxic pollutants coming from the air, soil, or the water ecosystem and, in this way, animals can develop health problems when exposed to high levels of pollutants. Reproductive failure and birth effects have been reported.

Eutrophication is occurring when elevated concentrations of nutrients (especially nitrogen) stimulate the blooming of aquatic algae, which can cause a disequilibration in the diversity of fish and their deaths.

Without a doubt, there is a critical concentration of pollution that an ecosystem can tolerate without being destroyed, which is associated with the ecosystem's capacity to neutralize acidity. The Canada Acid Rain Program established this load at 20 kg/ha/yr ( 120 ).

Hence, air pollution has deleterious effects on both soil and water ( 121 ). Concerning PM as an air pollutant, its impact on crop yield and food productivity has been reported. Its impact on watery bodies is associated with the survival of living organisms and fishes and their productivity potential ( 121 ).

An impairment in photosynthetic rhythm and metabolism is observed in plants exposed to the effects of ozone ( 121 ).

Sulfur and nitrogen oxides are involved in the formation of acid rain and are harmful to plants and marine organisms.

Last but not least, as mentioned above, the toxicity associated with lead and other metals is the main threat to our ecosystems (air, water, and soil) and living creatures ( 121 ).

In 2018, during the first WHO Global Conference on Air Pollution and Health, the WHO's General Director, Dr. Tedros Adhanom Ghebreyesus, called air pollution a “silent public health emergency” and “the new tobacco” ( 122 ).

Undoubtedly, children are particularly vulnerable to air pollution, especially during their development. Air pollution has adverse effects on our lives in many different respects.

Diseases associated with air pollution have not only an important economic impact but also a societal impact due to absences from productive work and school.

Despite the difficulty of eradicating the problem of anthropogenic environmental pollution, a successful solution could be envisaged as a tight collaboration of authorities, bodies, and doctors to regularize the situation. Governments should spread sufficient information and educate people and should involve professionals in these issues so as to control the emergence of the problem successfully.

Technologies to reduce air pollution at the source must be established and should be used in all industries and power plants. The Kyoto Protocol of 1997 set as a major target the reduction of GHG emissions to below 5% by 2012 ( 123 ). This was followed by the Copenhagen summit, 2009 ( 124 ), and then the Durban summit of 2011 ( 125 ), where it was decided to keep to the same line of action. The Kyoto protocol and the subsequent ones were ratified by many countries. Among the pioneers who adopted this important protocol for the world's environmental and climate “health” was China ( 3 ). As is known, China is a fast-developing economy and its GDP (Gross Domestic Product) is expected to be very high by 2050, which is defined as the year of dissolution of the protocol for the decrease in gas emissions.

A more recent international agreement of crucial importance for climate change is the Paris Agreement of 2015, issued by the UNFCCC (United Nations Climate Change Committee). This latest agreement was ratified by a plethora of UN (United Nations) countries as well as the countries of the European Union ( 126 ). In this vein, parties should promote actions and measures to enhance numerous aspects around the subject. Boosting education, training, public awareness, and public participation are some of the relevant actions for maximizing the opportunities to achieve the targets and goals on the crucial matter of climate change and environmental pollution ( 126 ). Without any doubt, technological improvements makes our world easier and it seems difficult to reduce the harmful impact caused by gas emissions, we could limit its use by seeking reliable approaches.

Synopsizing, a global prevention policy should be designed in order to combat anthropogenic air pollution as a complement to the correct handling of the adverse health effects associated with air pollution. Sustainable development practices should be applied, together with information coming from research in order to handle the problem effectively.

At this point, international cooperation in terms of research, development, administration policy, monitoring, and politics is vital for effective pollution control. Legislation concerning air pollution must be aligned and updated, and policy makers should propose the design of a powerful tool of environmental and health protection. As a result, the main proposal of this essay is that we should focus on fostering local structures to promote experience and practice and extrapolate these to the international level through developing effective policies for sustainable management of ecosystems.

Author Contributions

All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.

Conflict of Interest

IM is employed by the company Delphis S.A. The remaining authors declare that the present review paper was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

• News & Events
• Eastern and Southern Africa
• Eastern Europe and Central Asia
• Mediterranean
• Mexico, Central America and the Caribbean
• North America
• South America
• West and Central Africa
• IUCN Academy
• IUCN Contributions for Nature
• IUCN Library
• IUCN Red List of Threatened Species TM
• IUCN Green List of Protected and Conserved Areas
• IUCN World Heritage Outlook
• IUCN Leaders Forum
• Protected Planet
• Union Portal (login required)
• IUCN Engage (login required)
• Commission portal (login required)

Data, analysis, convening and action.

• Open Project Portal
• SCIENCE-LED APPROACH
• INFORMING POLICY
• SUPPORTING CONSERVATION ACTION
• GEF AND GCF IMPLEMENTATION
• IUCN CONVENING
• IUCN ACADEMY

The world’s largest and most diverse environmental network.

CORE COMPONENTS

• Expert Commissions
• Secretariat and Director General
• IUCN Council

• IUCN WORLD CONSERVATION CONGRESS
• REGIONAL CONSERVATION FORA
• CONTRIBUTIONS FOR NATURE
• IUCN ENGAGE (LOGIN REQUIRED)

IUCN tools, publications and other resources.

Get involved

Four IUCN economic case studies show the impacts of plastic pollution in the marine environment on biodiversity, livelihoods, and more in Africa and Asia

Research into the economic aspects of the Marine Plastics and Coastal Communities project, to contain and reduce plastic pollution in the ocean, delivers insight into the true costs of plastic pollution on communities, livelihoods, coasts, and the global ocean.

Photo: Adobe Stock Image

The objective

The Marine Plastics and Coastal Communities (MARPLASTICCs) project goal was to assist governments and regional bodies in Eastern and Southern Africa and Asia to promote, enact, and enforce legislation and other effective measures to contain and reduce plastic pollution in the ocean. Part of the research completed included defining an economic assessment approach and producing economics case studies that reflected the impacts of plastic pollution on the marine environment, on coastal livelihoods, and more.

National case studies

Four national level economic case studies are available: for Mozambique, South Africa, Thailand, and Viet Nam. The important economic sectors of fisheries and tourism were studied, using different lenses to examine how plastic pollution causes detrimental economic impacts at national and local levels. Each assessment differs and explores wide-ranging economic dimensions that should be considered when creating a national plan of action to mitigate marine litter and plastic pollution in the environment. From impacts upon export revenue, employment and food security, to the economic efficiency of beach cleaning in conjunction with deposit refund schemes, and the impact of ghost gear on fisheries, these four case studies take a reader into the true costs of plastic pollution on our global ocean and coastal communities.

Mozambique Economic Report

What is the impact of plastic pollution on fisheries – including the broader economic dimension relating to export revenue, employment, food security, and marine ecosystems, and biodiversity? This economic policy brief explains these impacts within the Republic of Mozambique.

South Africa: Efficiency of beach clean-ups and deposit refund schemes (DRS) to avoid damages from plastic pollution on the tourism sector in Cape Town, South Africa (2021)

What are the impacts of plastic pollution on tourism revenue and tourism employment? What is the efficiency of beach cleaning with the implementation of a DRS? What is the impact on employment after DRS implementation? This economic policy brief explains these impacts within the context of the city of Cape Town, South Africa.

Case study on net fisheries in the Gulf of Thailand

This issues brief presents the results of a study that estimated the impact of marine macroplastic on Thai net fisheries operating in the Gulf of Thailand. The study has estimated the reduction in the net fisheries’ revenue due to the plastic stock and annual flow into the fishing zone/Thai Exclusive Economic Zone (EEZ) (Gulf of Thailand).

The economic impact of marine plastics, including ghost fishing, on fishing boats in Phước Tinh and Loc An, Ba Ria Vung Tau Province, Viet Nam (2022)

What are the impacts of plastic pollution caused by abandoned, lost or otherwise discarded fishing gear (ALDFG), also known as ‘ghost gear’? What are the costs to biodiversity of ghost gear? This economic policy brief explains the impacts on fishing boats in Phước Tinh and Loc An, Ba Ria Vung Tau Province, Viet Nam.

On-the-ground work

The work IUCN is doing on the impacts of plastic pollution, especially on tourism, fisheries, and waste management aims to identify the plastic applications and polymers and the waste management gaps that are contributing to the global problem.

IUCN works on-the-ground with partners from NGOs, the private sector, and national governments, in order to determine the priority problems and the most effective interventions, to advise countries how to stop the problem within their specific national context. IUCN bring science and knowledge together with policy, for action, in this case economic policies can be examined for their role in dealing with plastic pollution.

As the world is now focused on the establishment of a global plastic pollution treaty , understanding the scope of the impacts and prioritising interventions – including economic interventions – will be needed.

Acknowledgments and Support

The Marine Plastics and Coastal Communities project (MARPLASTICCs), generously supported by the Swedish International Development Cooperation Agency (Sida), provided  support for the research and production of these Economic Case Studies.

For further information

• [email protected]

Related content

Today the European Commission proposed a new nature restoration law with binding targets on…

The BIODEV2030 project, launched in early 2020 supports the country's development ambition, while…

From 4 to 6 October in Malaga (Spain), the “International Bycatch Meeting” will demonstrate the…

Sign up for an IUCN newsletter

Plastic pollution on course to double by 2030 

Facebook Twitter Print Email

Plastic pollution in oceans and other bodies of water continues to grow sharply and could more than double by 2030, according to an  assessment  released on Thursday by the UN Environment Programme ( UNEP ). 

The report highlights dire consequences for health, the economy, biodiversity and the climate. It also says a drastic reduction in unnecessary, avoidable and problematic plastic, is crucial to addressing the global pollution crisis overall.  

To help reduce plastic waste at the needed scale, it proposes an accelerated transition from fossil fuels to renewable energies, the removal of subsidies and a shift towards more circular approaches towards reduction. 

Titled  From Pollution to Solution: a global assessment of marine litter and plastic pollution , the report shows that there is a growing threat, across all ecosystems, from source to sea. 

Solutions to hand 

Our oceans are full of plastic. A new @ UNEP assessment provides a strong scientific case for the urgency to act, and for collective action to protect and restore our oceans from source to sea. #CleanSeas https://t.co/97DMOZD3Ee pic.twitter.com/3xjthnsTh2 Inger Andersen andersen_inger

But it also shows that there is the know-how to reverse the mounting crisis, provided the political will is there, and urgent action is taken. 

The document is being released 10 days ahead of the start of the crucial UN Climate Conference,  COP26 , stressing that plastics are a climate problem as well.  

For example, in 2015, greenhouse gas emissions from plastics were 1.7 gigatonnes of CO2 equivalent; by 2050, they’re projected to increase to approximately 6.5 gigatonnes. That number represents 15 per cent of the whole global carbon budget - the​​ amount of greenhouse gas that can be emitted, while still keeping warming within the Paris Agreement goals. 

Recycling not enough 

Addressing solutions to the problem, the authors pour cold water on the chances of recycling our way out of the plastic pollution crisis. 

They also warn against damaging alternatives, such as bio-based or biodegradable plastics, which currently pose a threat similar to conventional plastics. 

The report looks at critical market failures, such as the low price of virgin fossil fuel feedstocks (any renewable biological material that can be used directly as a fuel) compared to recycled materials, disjointed efforts in informal and formal plastic waste management, and the lack of consensus on global solutions. 

Instead, the assessment calls for the immediate reduction in plastic production and consumption, and encourages a transformation across the whole value chain. 

It also asks for investments in far more robust and effective monitoring systems to identify the sources, scale and fate of plastic. Ultimately, a shift to circular approaches and more alternatives are necessary.  

Making the case for change 

For the Executive Director of UNEP, Inger Andersen, this assessment “provides the strongest scientific argument to date for the urgency to act, and for collective action to protect and restore our oceans, from source to sea.” 

She said that a major concern is what happens with breakdown products, such as microplastics and chemical additives, which are known to be toxic and hazardous to human and wildlife health and ecosystems. 

“The speed at which ocean plastic pollution is capturing public attention is encouraging. It is vital that we use this momentum to focus on the opportunities for a clean, healthy and resilient ocean”, Ms. Andersen argued.  

Growing problem 

Currently, plastic accounts for 85 per cent of all marine litter. 

By 2040, it will nearly triple, adding 23-37 million metric tons of waste into the ocean per year. This means about 50kg of plastic per meter of coastline. 

Because of this, all marine life, from plankton and shellfish; to birds, turtles and mammals; faces the grave risk of toxification, behavioral disorder, starvation and suffocation. 

The human body is similarly vulnerable. Plastics are ingested through seafood, drinks and even common salt. They also penetrate the skin and are inhaled when suspended in the air. 

In water sources, this type of pollution can cause hormonal changes, developmental disorders, reproductive abnormalities and even cancer. 

According to the report, there are also significant consequences for the global economy. 

Globally, when accounting for impacts on tourism, fisheries and aquaculture, together with the price of projects such as clean-ups, the costs were estimated to be six to 19 billion dollars per year, during 2018. 

By 2040, there could be a $100 billion annual financial risk for businesses if governments require them to cover waste management costs. It can also lead to a rise in illegal domestic and international waste disposal. 

The report will inform discussions at the  UN Environment Assembly  in 2022, where countries will come together to decide a way forward for more global cooperation. 

An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov . This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Pollution Prevention (P2)

Pollution prevention case studies.

• P2 case studies

Case study databases

P2 case studies.

Pollution prevention, E3: Economy, Energy and Environment and Green Suppliers Network case studies searchable by keyword, title, year, sector, and process used in achieving results. P2 Case Studies: search by keyword or output saved (water, energy, GHG, etc.). Please use quotes at the beginning and end of the search terms if you are looking for an exact expression. For example, when you are looking for Region 3 case studies, type "Region 3" in the search area.

The following links exit the site Exit

Region 6 Success Stories Database - Southwest Network for Zero Waste .

The P2 InfoHouse is a searchable online collection of more than 50,000 pollution prevention (P2) related publications, fact sheets, case studies and technical reports .

E3 Success Stories . Case studies from the Green Suppliers Network and the E3: Economy - Energy - Environment programs.

P2 Impact at GreenBiz.com . Various case studies in different sectors.

Top of Page

The case studies, success stories, and P2 profiles contained in this database were developed under Pollution Prevention Grants awarded by the U.S. Environmental Protection Agency. They have not been formally reviewed by EPA. The views expressed are solely those of the grantee. The product is not an EPA product and does not reflect the views and policies of the Agency. The EPA does not endorse trade names or recommend the use of commercial products mentioned in these documents.

Contact Us to ask a question, provide feedback, or report a problem.

• Feeling Distressed?
• A-Z Listing
• Academic Calendar
• People Directory

Scientists develop framework to measure plastic emissions and bolster U.N. efforts to reduce pollution

Sean Bettam

University of Toronto scientists have developed a framework for measuring plastic pollution emissions akin to the global standard for measuring greenhouse gas emissions. 

The researchers say the approach will boost identification of the biggest contributors to plastic pollution from local to national levels and improve strategies in reducing emissions worldwide. The framework arrives ahead of international discussions in Ottawa from April 23 to 29 led by the United Nations’ Intergovernmental Negotiating Committee on Plastic Pollution towards a legally binding global agreement on plastic pollution.

Using Toronto as a model, the researchers developed the first-of-its-kind framework and estimated that in one year alone, Toronto emitted nearly 4,000 tonnes of plastic pollution.

“That’s roughly 400 garbage trucks’ worth of plastic that leaks into the environment annually from across the city,” said Alice (Xia) Zhu , lead author of a study outlining the method published in Environmental Science & Technology and a U of T Scarborough PhD candidate working with Assistant Professor Chelsea Rochman in the Department of Ecology & Evolutionary Biology at U of T. 

“Assigning responsibility for the pollution to a jurisdiction with the ability to enact laws means there is no hiding where the pollution came from. It presents an opportunity to identify major sources of plastic pollution within the area and inform measures to curb these emissions.”

Zhu and colleagues at U of T and the Rochester Institute of Technology took inspiration from guidelines for compiling emissions inventories of greenhouse gases established by the Intergovernmental Panel on Climate Change. Adapting for physical differences between greenhouse gases and solid pieces of plastic, the researchers used a similar methodology of identifying the major pollution-generating activities in a particular area, calculating the amount of pollution generated by each activity within a given period, and accounting for uncertainties associated with each source of pollution-generating activity.

“Our goal was to develop an accounting mechanism or tool for measuring plastic emissions that any level of government can adopt,” said Zhu, who is pursuing a PhD in environmental science in the Department of Physical & Environmental Sciences at U of T Scarborough. “But most importantly, we hope this tool we have introduced will allow the plastic field to follow in the footsteps of the climate field, where countries submit national emissions inventories to an international body such as the United Nations to track our progress towards reaching a globally defined target.” Currently, national emissions inventories of plastic pollution do not exist, nor does a globally defined target for reducing plastic pollution.

To demonstrate the utility of the framework, the researchers built an emissions inventory of plastic pollution for the City of Toronto for the year 2020 drawn from publicly available data gathered through municipal litter audits and other sources. From a list of nine types of sources — including littering, tire dust from airplanes and on-road vehicles, washing machines, and paint from road markings and the exteriors of houses – they estimated between 3,531 and 3,852 tonnes of plastic pollution were emitted from within the city’s boundaries during the period.

Littering made up the largest share at 3,099 tonnes while artificial turf was responsible for the most emissions of microplastics — particles less than five millimetres in diameter — at 237 tonnes.

“It is not surprising that larger materials – known as macroplastics, and in this case from mismanaged waste such as littering — made up the majority of the mass. But it overshadows the small stuff, microplastics,” said Rochman, a co-author of the study and Zhu’s PhD supervisor. “Microplastics tend to be the highest by count in terms of actual pieces. This suggests that policies relevant to microplastics, in addition to macroplastics, are critical to reduce plastic emissions in the City of Toronto.”

The researchers selected Toronto to test the framework as it is the largest city in Canada and the fourth-largest city in North America. “It’s an urban hub for various activities, and where you have lots of people and activity, you inevitably generate a lot of pollution,” said Zhu. “For a successful and informative case study, you want to look at a place with a lot of different sources of pollution. By doing so, you can identify which sources should be prioritized for the reduction of pollution out of all the others, and thereby demonstrate the utility of an emissions inventory for informing local policy.”

Zhu said emissions inventories of plastic pollution must be a foundational piece of a successful global treaty on plastic, and that the framework should be applied to other cities, provinces and states, and countries around the world to better understand what kinds of plastic pollution are being released into the environment.

“The guidelines can be applied to regions worldwide, regardless of what kinds of sources are there,” Zhu said. “Each geographic region will have different characteristics and the inventory will allow for the development of solutions tailored to that specific region.”

Related News

PhD candidate explores potential uneven impacts in transit investment along Eglinton LRT

Tips from an astrophysicist on the best ways to enjoy the solar eclipse near Toronto

Whether checking the news or escaping problems, the reasons we use X (Twitter) impact our wellbeing

• Open access
• Published: 14 April 2024

The impact of indoor air pollution on children’s health and well-being: the experts’ consensus

• Elena Bozzola   ORCID: orcid.org/0000-0003-2586-019X 1 ,
• Rino Agostiniani 2 ,
• Laura Pacifici Noja 3 ,
• Jibin Park 3 ,
• Paolo Lauriola 4 ,
• Tiziana Nicoletti 5 ,
• Domenica Taruscio 6   na1 ,
• Giovanni Taruscio 6   na1 &
• Alberto Mantovani 6   na1  

Italian Journal of Pediatrics volume  50 , Article number:  69 ( 2024 ) Cite this article

129 Accesses

Metrics details

Pollution of the indoor environment represents a concern for human health, mainly in case of prolonged exposure such as in the case of women, children, the elderly, and the chronically ill, who spend most of their time in closed environments.

The aim of the study is to organize a group of experts in order to evaluate the evidence and discuss the main risk factors concerning indoor air and the impact on human health as well as challenging factors regarding preventive strategies to reduce pollution. The experts highlighted the main risk factors concerning indoor air, including poor ventilation, climatic conditions, chemical substances, and socio-economic status. They discussed the impact on human health in terms of mortality and morbidity, as well as challenging factors regarding preventive strategies to reduce pollution.

The experts identified strategies that can be reinforced to reduce indoor pollution and prevent negative consequences on human health at national and local levels.

Pollution is becoming day after day an alarming threat to our planet. The international and national public health agencies have significantly focused on addressing food pollution, particularly concerning pesticide residues and bioaccumulating substances. Additionally, they have directed considerable efforts towards combating outdoor atmospheric pollution, stemming from emissions in urban areas, industrial facilities, and vehicle exhaust. Meanwhile, whereas people in high-income Countries (HICs) spend much of their lives indoors, the pollution of the indoor environment has still to receive due attention [ 1 , 2 , 3 ]. Indeed, domestic air and indoor pollution can be traced back to prehistory, when humans first moved to temperate climates, started building shelters, and used fire for cooking, heating, and lighting.

Indoor pollution is a global health issue. Today around the world, around 2.4 billion people still cook using solid fuels (such as wood, agricultural waste, coal, and manure) and kerosene on fires or stoves. Most of these people are poor and live in low- and middle-income countries with a large discrepancy between urban and rural areas. In 2020, only 14% of individuals residing in urban areas depended on polluting fuels and technologies, starkly contrasting the 52% prevalence observed among the global rural population [ 4 ].

Despite transitioning from biomass fuels to petroleum products and electricity accompanying modernization in developed countries, pollution remains a persistent threat to public health [ 5 ].

Indoor pollution is generated by the use of inefficient and polluting fuels, technologies, and/or materials at home and in closed spaces where people spend most of their time, including schools, healthcare facilities, gyms, and entertainment structures (cinemas, museums, etc.). Indoor air can be even more polluted than outdoor air when ventilation is inadequate and/or when heat and humidity facilitate the concentration of allergens, infectious agents, dust, etc [ 3 , 6 ]. Besides, exposure to indoor pollutants can be greater than outdoor also because the amount of time people spend inside confined environments may be greater [ 3 ]. Therefore, whereas exposure is a problem for everyone, the concern is even greater for women, children (e.g. schools), the elderly (e.g. retirement homes), and the chronically ill, who spend most of their time at home and in other closed environments; moreover, indoor pollution is greater in relation to lower socio-economic status [ 4 , 7 ].

The main exposure to indoor pollutants is through inhalation; nevertheless, it is crucial to consider cutaneous and oral exposure, particularly among children who engage in activities that involve contact with floors and frequently exhibit hand-to-mouth interactions [ 8 , 9 ]. Wilson’s study revealed that children touch their mouths, eyes, and nose more frequently than adults. In particular, hand-to-mouth contact may be a matter of concern when considering exposures to chemicals, such as lead or pesticides [ 8 ].

The KOS Study Center - Science, Art, Society organized the working table “Living and working in healthy environments: indoor air, construction materials, furniture” to draw attention, evaluate the evidence, and discuss future perspectives regarding the impacts on human health and well-being of the quality of indoor environments in which the majority of people spend time.

An interdisciplinary group of experts highlighted the complexity of the indoor environment. The experts have been selected based on their level of expertise and professional experience in indoor pollution or as delegates from Italian Scientific Societies or Associations. An electronic search was undertaken on the PubMed database, using all of the important concepts from our basic clinical question, avoiding unnecessary filters. So, the terms “air pollution indoor” and “air quality, indoor” have been used as Mesh Terms, limited to humans and English reports. The database was shared and the objectives of the consensus were discussed on September 30th, 2023. Since then, each expert has independently analyzed the texts and their references. On December 11th, 2023 the experts discussed and highlighted the main risk factors concerning indoor air and the impact on human health as well as challenging factors regarding preventive strategies to reduce pollution.

Accordingly, the three identified topics examined are: identification of the main risk factors for indoor air and environment; investigation of the impact of indoor pollution on human health; and highlighting challenging factors regarding prevention and health risk reduction.

Main risk factors concerning indoor air and environment

Certain individual risk factors are rather well-recognized, including infections via air conditioning, allergens, radon, and passive tobacco smoking, yet, the scenario of indoor risk factors is far more complex and calls for a comprehensive appraisal. The group of experts identified the main risk factors for the quality of indoor air which require further evaluation: poor ventilation, climatic factors, chemical substances, and low socio-economic status.

Poor ventilation

In poorly ventilated areas, fine particle levels may be 100 times higher than acceptable levels and may result in respiratory diseases such as asthma, allergy, and sick-building symptoms. In addition, improving on indoor ventilation system reduces the humidity, thus inhibiting the growth of microbes [ 4 , 10 , 11 ]. Monitoring the maintenance of the ventilation system is essential to ensure proper functionality, as dirty filters and blocked vents can impede the circulation of air [ 12 ]. The problem is of concern especially if we consider school buildings, where children spend up to 8 h a day in classrooms, at least between the ages of 6 and 19 years, and in many cases between 3 and 4 and 19 years. The conditions are often unacceptable and regardless of the geographic situation, all the current studies report similar problems: classrooms too small for the number of children in school classes, resulting in densely crowded rooms, as well as poorly conceived and managed ventilation [ 13 ]. Classrooms generally accommodate a large number of people and therefore require a certain air exchange in order to maintain low levels of carbon dioxide and other pollutants, as well as to allow children to spend a comfortable and profitable school time. Nevertheless, high carbon dioxide concentrations in classrooms, which indicate poor ventilation conditions, have been identified as the primary causes of poor indoor air quality in schools [ 13 ]. A good system of ventilation is a key factor. Evidence suggests that the level of exposure to indoor pollution is lower in classrooms placed on higher floors of buildings, which is likely due to better ventilation [ 14 ].

Climatic conditions

The ongoing and progressive changes in climate and ambient air pollutant concentrations have a significant impact on the quality of indoor air and the way people live in all regions of the world, especially on children due to their vulnerability. Climatic factors, including temperature and humidity, can affect the quality of indoor air as well as increase the risk of viral, bacterial, and fungal contamination [ 10 , 15 ]. The study by Fan investigated that indoor fungal contamination is highest in the summer. This derives researchers into a concern about the population living in the tropical region. In turn, this event may elicit an increased use of fungicides, insecticides, and biocides [ 16 ]. Moreover, environmental alteration, such as land reduction, deforestation, etc., facilitates poor climatic conditions in the indoor environment as well as outdoor-to-indoor exposure to harmful emissions and infectious agents [ 17 ].

Chemical substances

Indoor environments present a large quantity of materials, with the presence of additives in paints, glues, fabrics, coverings, furnishings, electronic equipment, and more. Additionally, the prevalence of recycled materials in concrete contributes to the complexity of indoor settings. For example, indoor exposure to benzene (from glues, paints, and solvents) can be even higher than that in industrial environments; the same applies to carcinogenic formaldehyde used as a preservative in woods and textiles [ 18 ]. Among these substances, endocrine disruptors (ED) are particularly dangerous for children and pregnant women, as they are linked to reproductive and developmental disorders. In children, epidemiological studies suggest that ED may adversely affect prenatal and post-natal growth, thyroid function, glucose metabolism, body composition, and risk of obesity, puberty onset, and successive fertility through several mechanisms [ 19 , 20 ]. These substances (including parabens, phthalates, bisphenols, and perfluoroalkyl substances) may be used as preservatives, biocides, and water repellents. For example, polybrominated chemicals have been widely used as flame retardants, while triazoles (steroid synthesis inhibitors) are fungicides intended for wood preservation. Substances identified as ED are subject to restrictions, but they can persist in materials and consequently in indoor dust [ 21 ]. For example, the exposure to polybrominated diphenyl ethers used in paints, plastics, foam furniture padding, textiles, rugs, curtains, televisions, building materials, airplanes, and automobiles, banned since 2006, may cause concerns for human health. In fact, due to their long persistence, they may leak from products over time and accumulate in the environment and humans for many years: several toxicological and epidemiological studies (also recently reviewed by the European Food Safety Authority (EFSA) indicate that the PBDE body burden is associated with adverse reproductive and neurobehavioral effects, especially in the developing organism; main modes of action are the disruption of thyroid and steroid hormone metabolism as well as oxidative stress [ 22 , 23 , 24 ].

Low socio-economic status

Data published by the World Health Organization (WHO) show that poverty can exacerbate the harmful health effects of air pollution by limiting access to information, treatment, and other health resources. For example, considering fuels and polluting technologies for cooking, the problem is above all in low- and middle-income countries. It is a matter of concern for 83% of the population in the African Region, 59% in the South-East Asia Region, and 42% in the Western Pacific Region. In the Americas and the European Region numbers are significantly lower, 13% and 6% respectively. Nevertheless, even in the WHO European Region, more than 1 out of 20 people is exposed to polluting cooking technologies [ 1 ].

Besides poverty, lower economic status with outdated, inadequate housing devices may represent one of the main sources of pollution in HICs. For example, in the European Union, cookers can produce much higher levels of indoor nitrogen dioxide pollution than outdoor ones. They can also cause carbon monoxide pollution. Replacing a gas stove with an electric one can decrease the median ambient nitrogen dioxide concentration by 51% [ 25 , 26 ]. Cooking methods may influence indoor air quality (for example, roasting meat produces more PM2.5 than boiled food); in addition, also the dimension of the kitchen is an essential factor [ 27 , 28 ]. The concentration of pollutants resulting from cooking the same meal is greater in a small environment rather than in a large kitchen [ 28 ].

The impact of indoor pollution on human health

The experts focused on the effect of indoor pollution on both mortality and morbidity:

Environmental pollution in 2019 had been responsible for approximately 9 million deaths per year, corresponding to one in six deaths worldwide [ 29 ]. In detail, according to WHO, the combined effects of ambient air pollution and household air pollution are associated with 6.7 million premature deaths annually [ 30 ]. Of note, 2.4 billion people worldwide (approximately one-third of the whole population) cook by open fires or inefficient stoves fuelled by kerosene, biomass, and coal, which are responsible for household air pollution [ 4 ]. Household air pollution was responsible for an estimated 3.2 million deaths per year in 2020, including over 237,000 deaths of children under the age of 5.

Adverse effects of indoor pollution may be traced to respiratory and non-respiratory systems. In the literature, there is strong evidence that children should be considered as a susceptible group as they are more susceptible to the health effects of air pollution than adults. The functionality of children’s immune and respiratory systems is still developing, hence increasing the vulnerability to exposure to environmental pollutants in indoor air and dust. Exposure can occur in diverse scenarios and settings. Apart from home, they can be exposed to indoor air pollution also in nursery and primary schools; in these settings, there may be a continuum between indoor and outdoor pollution, e.g., through the journeys to school and school playgrounds [ 3 ]. Indeed, nearby traffic is a key determinant of pollutant concentrations outside schools, which is relevant to indoor exposure through outdoor-indoor exchanges [ 3 ]. Moreover, at school, children are frequently more physically active than at home, increasing the ventilation rate and consequently the inhaled dose of pollutant concentrations [ 31 ]. Exposure to traffic-related air pollutants at school can also adversely impact neuropsychological development, in particular cognitive development, mainly memory and attention, as observed in primary school children [ 32 ]. Exposure to household air pollution nearly doubles the risk of childhood lower respiratory tract infections and is responsible for increased risk of non-communicable diseases, including stroke, ischemic heart disease, chronic obstructive pulmonary disease, and lung cancer [ 33 , 34 , 35 , 36 ]. A meta-analysis of 41 studies has shown that children living in a home with a gas stove have a 32% increased risk of developing asthma attacks [ 37 ]. Finally, indoor air pollution can contribute to aggravating airborne infections. Of note, an association between COVID-19 infection and pollution has been described during the pandemic period [ 38 ]. As mentioned before in the case of ED, adverse effects of indoor pollution are not limited to the respiratory system. For example, there is a connection between pollution and weight gain [ 35 ]. The main pollutants involved in this process are nitrogen oxides, nitrogen dioxide, ozone, and particulate matter, including PM10 and PM2.5 [ 26 , 35 , 39 ].

Indoor pollution may constitute a risk factor for future generations, inducing negative effects on health even before birth. Both prenatal and postnatal exposure to air pollution can negatively affect neurological development, lead to poorer cognitive test results, and influence the development of behavioral disorders such as autism spectrum disorders and attention deficit hyperactivity disorder. In particular, the role of pollution in an increased risk of neurodevelopmental disorders, anxiety, and depressive disorders even before birth has been highlighted [ 40 , 41 , 42 ]. As well, there is also a link between household air pollution, low birth weight, and reduced respiratory lung function [ 41 ].

Challenging factors regarding prevention and health risk reduction

Indoor contaminants are invisible and odorless, so they can be defined as unknown enemies. In most cases, people are unaware of some chemical, biological, and physical products that are present inside houses. Scarce attention by public health agencies and policy makers as well as inadequate information and knowledge lead to underestimating the problem with long-term effects on the entire community. Of note, attention is present to isolated specific factors, but a comprehensive framework for primary prevention and risk analysis is lacking [ 15 , 43 ].

In 2014, WHO issued the first guidelines on clean fuels and technologies for cooking, heating, and home lighting. The document aimed to guide policymakers and specialists working on energy and resources to implement the best strategies against household air pollution. Experts highlighted the importance of expanding the use of clean fuels and technologies including solar energy, electricity, biogas, liquefied petroleum gases, natural gas, alcohol fuels, as well as biomass stoves in line with the emission targets by WHO guidelines. Overall, while the WHO Guidelines need to be updated in order to build a comprehensive concept of the complex indoor scenario, their indications still retain their full validity. It is, therefore, necessary to rethink the settlement models in order to place living and the well-being of the person at the center of urban planning and housing [ 26 ].

Studies on indoor pollution should be increased to expand the knowledge and reduce remaining uncertainties. In particular, it is necessary to delve deeper into how the various pollutants circulate, how they interact with each other, and how they are influenced by climate change and other environmental drivers. These actions are consistent with the United Nations Agenda 2030 for sustainable development and for addressing inequalities in terms of health. A global health strategy and a transdisciplinary One Health approach are recommended for the integrated protection of all living beings and of the environment: conceivable and feasible regulatory measures for primary prevention include enforcing evidence-based limits for unavoidable pollutants and replacing hazardous substances and technologies. At a national and local level, in any home and indoor environment, through awareness raising and empowerment, it is possible to implement corrective strategies such as minimizing the lighting of fireplaces, using extractor hoods while cooking to avoid fumes and steam, clean air conditioning filters regularly [ 44 ].

At a national and local level, in any home and indoor environment, strategies should be reinforced to reduce indoor pollution and prevent negative consequences on human health, requiring risk analysis, institutional commitment, and funding as well as the necessary involvement of policymakers.

The main actions that the expert group has identified are:

In conclusion, the experts agree on the urgent need for an approach to indoor air and the environment from a health risk assessment and management perspective, advocating policymakers and health care providers in finalizing strategies to reduce indoor pollution. Medical training as well as epidemiological and clinical studies should strengthen and disseminate the knowledge on indoor pollution and its health effects. Concrete directions and anticipatory guides may include scientific reports as well as awareness-raising campaigns on indoor air and environment; campaigns should be addressed to the general population, and children-tailored initiatives should be considered as well. These actions work on a cascade with a final desirable positive effect on the health of the population.

In detail, the suggested actions of policymakers, medical doctors, and the population are:

Publishing periodic regional and national updates of indoor pollution levels using appropriate indicators. There are variable national and regional limit values for gaseous substances and airborne particulate matter in the built environment, including schools, homes, healthcare facilities, and other public spaces. Moreover, indoor spaces are characterized by complex air chemistry, and their construction materials and types of activities vary significantly. Hence, a harmonization effort should be done to avoid unjustified differences in limit values based on up-to-date evidence and reasonable precaution.

Integrating local health networks. The indoor environment is variable, dynamic, and complex, considering the problems of solid–gas partitioning onto surfaces and particles, as well as the release and distribution of particles from different materials. Science-based models and approaches will help in order not to “drown in complexity”. Meanwhile, models and approaches for research on indoor air and environment are not harmonized, therefore, the opportunity for cross-study comparisons is missed. Indoor air chemistry is subject to specific boundary conditions; the required guidance documents for indoor-specific pollutants need to be developed in collaboration with local health networks. In general, interdisciplinary studies carried out through harmonized, comparable approaches by local health networks will be important to support and/or update specific regulations.

Creating a permanent national task force for the epidemiological surveillance of the effects of indoor pollution and the definition of risk analysis and health promotion strategies by timely actions.

Organizing training experiences based on local needs, with the contribution of civic organizations.

Planning preventive and corrective interventions, including redevelopment of unhealthy buildings and polluted areas, implementation of energy efficiency of the real estate assets (public and private), selection of low-hazard materials, renaturalization, and incentives for the greening of surfaces at homes, schools, and workplaces.

Providing sentinel doctors who can provide regular and standardized information by using appropriate indicators, and timely organized interventions as well as punctual and effective preventive actions.

Training on environment and pollution during medical degree courses and other health (e.g. prevention technicians) and non-health (e.g. engineering, architecture) faculties.

Medical training to promote awareness and knowledge of the genesis, extent, and modalities of the effects of the indoor environment on the health of the current and future generations, through the knowledge of environmental, social, and cultural determinants and their interactions.

Encouraging epidemiological and clinical research on the age- and gender-specific effects of indoor pollution, advocating national scientific studies. A large body of scientific studies has shown that exposure to indoor air pollutants has adverse effects on children’s health, both in the short term and long term, including reduced cognitive function, heart and respiratory disturbances, as well as increased predisposition to stroke, chronic obstructive pulmonary disease, and lung cancer. For this reason, increasing knowledge on indoor air pollution is helpful to promote public health, reduce de community disease burden as well as support policymakers in developing management approaches to the indoor environment from a health risk management perspective.

Information, awareness, and education of the population through family doctors and pediatricians. They can play a crucial role in increasing awareness, knowledge, and empowerment, promoting actions to preserve human health. Other professional categories, such as pharmacists, surveyors, construction workers unions, and condominium administrators, as well as civic organizations, should play a key role in spreading information. The involvement of the school system should be kept in mind in order to aware the new generations.

Limitations

It should be mentioned that the chosen database (PubMed) focused on peer-reviewed literature, not including grey literature, such as working papers, opinions, and reports. The work team was chosen to identify available national experts, not including international ones, and did not face policymakers.

Data availability

Not applicable.

Abbreviations

endocrine disruptors

World Health Organization

WHO. Air pollution and child health: prescribing clean air. https://www.who.int/publications/i/item/WHO-CED-PHE-18-01 .

UNICEF. Clear the Air for Children. 2016. https://www.unicef.org/reports/clean-air-children .

Osborne S, Uche O, Mitsakou C, Exley K, Dimitroulopoulou S. Air quality around schools: part I - A comprehensive literature review across high-income countries. Environ Res. 2021;196:110817.

Article   CAS   PubMed   Google Scholar  

WHO. Household air pollution 28 November 2022. https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health .

IEA IRENA, World Bank UNSD, Tracking WHO. SDG 7: The Energy Progress Report. World Bank, Washington DC. © World Bank. License: Creative Commons Attribution—NonCommercial 3.0 IGO (CC BY-NC 3.0 IGO). https://trackingsdg7.esmap.org/downloads.

Baloch RM, Maesano CN, Christoffersen J, Banerjee S, Gabriel M, Csobod É, de Oliveira Fernandes E, Annesi-Maesano I, SINPHONIE Study group. Indoor air pollution, physical and comfort parameters related to schoolchildren’s health: data from the European SINPHONIE study. Sci Total Environ. 2020;739:139870.

Coelho C, Steers M, Lutzler P, Schriver-Mazzuoli L. Indoor air pollution in old people’s homes related to some health problems: a survey study. Indoor Air. 2005;15(4):267–74.

Wilson AM, Verhougstraete MP, Beamer PI, King MF, Reynolds KA, Gerba CP. Frequency of hand-to-head,-mouth,-eyes, and-nose contacts for adults and children during eating and non-eating macro-activities. J Expo Sci Environ Epidemiol. 2021;31(1):34–44.

Article   PubMed   Google Scholar  

Maung TZ, Bishop JE, Holt E, Turner AM, Pfrang C. Indoor air Pollution and the health of vulnerable groups: a systematic review focused on Particulate Matter (PM), volatile Organic compounds (VOCs) and their effects on children and people with Pre-existing Lung Disease. Int J Environ Res Public Health. 2022;19(14):8752.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Qiu Y, Zhou Y, Chang Y, Liang X, Zhang H, Lin X, Qing K, Zhou X, Luo Z. The effects of Ventilation, Humidity, and temperature on bacterial growth and bacterial genera distribution. Int J Environ Res Public Health. 2022;19(22):15345.

Wargocki P. The effects of ventilation in homes on health. Int J Vent. 2013;12(2):101–18.

Google Scholar  

WHO. Roadmap to improve and ensure good indoor ventilation in the context of COVID-19 https://www.who.int/publications/i/item/9789240021280 .

Salthammer T, Uhde E, Schripp T, Schieweck A, Morawska L, Mazaheri M, Clifford S, He C, Buonanno G, Querol X, Viana M, Kumar P. Children’s well-being at schools: impact of climatic conditions and air pollution. Environ Int. 2016;94:196–210.

Zhang LJ, Guo C, Jia X, Xu H, Pan M, Xu D, Shen X, Zhang J, Tan J, Qian H, et al. Personal exposure measurements of school-children to fine particulate matter (PM 2.5 ) in winter of 2013, Shanghai, China. PLoS ONE. 2018;13:e0193586.

Article   PubMed   PubMed Central   Google Scholar  

Vardoulakis S, Giagloglou E, Steinle S, Davis A, Sleeuwenhoek A, Galea KS, Dixon K, Crawford JO. Indoor exposure to selected air pollutants in the Home Environment: a systematic review. Int J Environ Res Public Health. 2020;17(23):8972.

Fan G, Xie J, Yoshino H, Yanagi U, Zhang H, Li Z, Li N, Lv Y, Liu J, ^Zhu S, Hasegawa K, Kagi N, Liu J. Investigation of fungal contamination in urban houses with children in six major Chinese cities: genus and concentration characteristics. Build Environ. 2021;205:108229.

Article   Google Scholar  

Davey TM, Selvey LA. Relationship between Land Use/Land Use Change and Human Health in Australia: a scoping study. Int J Environ Res Public Health. 2020;17(23):8992.

Grant TL, Wood RA. The influence of urban exposures and residence on childhood asthma. Pediatr Allergy Immunol. 2022;33:e13784.

Hassan S, Thacharodi A, Priya A, Meenatchi R, Hegde TA, Nguyen RT. Pugazhendhi A endocrine disruptors: unravelling the link between chemical exposure and women’s reproductive health. Environ Res. 2023;241:117385.

Predieri B, Iughetti L, Bernasconi S, Street ME. Endocrine disrupting Chemicals’ effects in children: what we know and what we need to learn? Int J Mol Sci. 2022;23(19):11899.

Zheng K, Zeng Z, Lin Y, Wang Q, Tian Q, Huo X. Current status of indoor dust PBDE pollution and its physical burden and health effects on children. Environ Sci Pollut Res Int. 2023;30(8):19642–61.

Rudel RA, Perovich LJ. Endocrine disrupting chemicals in indoor and outdoor air. Atmos Environ. 2009;43(1):170–81.

Article   CAS   PubMed Central   Google Scholar  

Kronborg TM, Hansen JF, Rasmussen ÅK, Vorkamp K, Nielsen CH, Frederiksen M, Hofman-Bang J, Hahn CH, Ramhøj L. Feldt-Rasmussen U the flame retardant DE-71 (a mixture of polybrominated diphenyl ethers) inhibits human differentiated thyroid cell function in vitro. PLoS ONE. 2017;12(6):e0179858.

EFSA Panel on Contaminants in the Food. Chain (CONTAM) update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food. EFSA J. 2024;22:e8497.

Paulin LM, Diette GB, Scott M, McCormack MC, Matsui EC, Curtin-Brosnan J, Williams DL, Kidd-Taylor A, Shea M, Breysse PN, Hansel NN. Home interventions are effective at decreasing indoor nitrogen dioxide concentrations. Indoor Air. 2014;24(4):416–24.

WHO. WHO global air quality guidelines: particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. https://www.who.int/publications/i/item/9789240034228 .

Li YC, Qiu JQ, Shu M, Ho SSH, Cao JJ, Wang GH, Wang XX, Zhao XQ. Characteristics of polycyclic aromatic hydrocarbons in PM 2.5 emitted from different cooking activities in China. Environ Sci Pollut Res Int. 2018;25(5):4750–60.

EPHA The Public Health and Environmental Impacts of Cooking with Gas. https://epha.org/wp-content/uploads/2023/06/the-public-health-and-environmental-impacts-of-cooking-with-gas-.pdf .

Fuller R, Landrigan PJ, Balakrishnan K, Bathan G, Bose-O’Reilly S, Brauer M, Caravanos J, Chiles T, Cohen A, Corra L, Cropper M, Ferraro G, Hanna J, Hanrahan D, Hu H, Hunter D, Janata G, Kupka R, Lanphear B, Lichtveld M, Martin K, Mustapha A, Sanchez-Triana E, Sandilya K, Schaefli L, Shaw J, Seddon J, Suk W, Téllez-Rojo MM, Yan C. Pollution and health: a progress update. Lancet Planet Health. 2022;6:e535–47.

WHO Ambient. (Outdoor) Air Pollution, https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health?gclid=CjwKCAiAg9urBhB_EiwAgw88mb24c_ngWBsT2075fCWlCShgf83LI29xC4dKWS3ikqX2p4dLdT3bMRoC_ekQAvD_BwE ).

Branco PTBS, Alvim-Ferraz MCM, Martins FG, Ferraz C, Vaz LG, Sousa SIV. Impact of indoor air pollution in nursery and primary schools on childhood asthma. Sci Total Environ. 2020;745:140982.

Forns J, Dadvand P, Esnaola M, Alvarez-Pedrerol M, López-Vicente M, Garcia-Esteban R, Cirach M, Basagaña X, Guxens M, Sunyer. Longitudinal association between air pollution exposure at school and cognitive development in school children over a period of 3.5 years. J Environ Res. 2017;159:416–21.

Article   CAS   Google Scholar  

Yu Z, Merid SK, Bellander T, Bergström A, Eneroth K, Georgelis A, Hallberg J, Kull I, Ljungman P, Klevebro S, Stafoggia M, Wang G, Pershagen G, Gruzieva O, Melén E. Associations of improved air quality with lung function growth from childhood to adulthood: the BAMSE study. Eur Respir J. 2023;61(5):2201783.

Fucic A. Chapter 15: Endocrine Disruptors in Building Materials. in: Challenges in Endocrine Disruptor Toxicology and Risk Assessment (ed, by A. Mantovani and A. Fucic), Royal Society of Chemistry.2020. London 377–388.

Parasin N, Amnuaylojaroen T, Saokaew S. Effect of Air Pollution on obesity in children: a systematic review and Meta-analysis. Child (Basel). 2021;8(5):327.

Paciência I, Cavaleiro Rufo J, Moreira A. Environmental inequality: air pollution and asthma in children. Pediatr Allergy Immunol. 2022;33(6).

Lin W, Brunekreef B, Gehring U. Meta-analysis of the effects of indoor nitrogen dioxide and gas cooking on asthma and wheeze in children. Int J Epidemiol. 2013;42(6):1724–37.

Romeo A, Pellegrini R, Gualtieri M, Benassi B, Santoro M, Iacovelli F, Stracquadanio M, Falconi M, Marino C, Zanini G, Arcangeli C. Experimental and in silico evaluations of the possible molecular interaction between airborne particulate matter and SARS-CoV-2. Sci Total Environ. 2023;895:165059.

Zhu L, Hajeb P, Fauser P, Vorkamp K. Endocrine disrupting chemicals in indoor dust: a review of temporal and spatial trends, and human exposure. Sci Total Environ. 2023;874:162374.

Zundel CG, Ryan P, Brokamp C, Heeter A, Huang Y, Strawn JR, Marusak HA. Air pollution, depressive and anxiety disorders, and brain effects: a systematic review. Neurotoxicology. 2022;93:272–300.

Gascon M, Vrijheid M, Nieuwenhuijsen MJ. The Built Environment and Child Health: an overview of current evidence. Curr Environ Health Rep. 2016;3(3):250–7.

Yang JH, Strodl E, Wu CA, Yin XN, Wen GM, Sun DL, Xian DX, Chen JY, Chen YJ, Chen J, Chen WQ. Association between prenatal exposure to indoor air pollution and autistic-like behaviors among preschool children. Indoor Air. 2022;32(1):e12953.

Vrijheid M. The Exposome: a New Paradigm to study the Impact of Environment on Health. Thorax. 2014;69:876–8.

United Nations. Transforming our world: the 2030 Agenda for Sustainable Development. https://sdgs.un.org/2030agenda .

Download references

Acknowledgements

the other members of the expertise group: Leonello Attias (Istituto Superiore di Sanità), Paolo Carrer (Università degli Studi di Milano), Agostino Macrì (Unione Nazionale Consumatori), Gaetano Settimo, (Istituto Superiore di Sanità, Presidente della Società Italiana Indoor Air Quality), Francesco Saverio Violante (Azienda Ospedaliero-Universitaria di Bologna e Direttore del Programma di ricerca su Lavoro e salute).

This work was supported also by the Italian Ministry of Health with “current Research funds”.

Author information

Domenica Taruscio, Giovanni Taruscio and Alberto Mantovani contributed equally to this work.

Authors and Affiliations

Pediatric Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy

Elena Bozzola

The Italian Pediatric Society, Rome, Italy

Rino Agostiniani

Saint Camillus International University of Health Sciences, Rome, Italy

Laura Pacifici Noja & Jibin Park

Rete Italiana Medici Sentinella per l’Ambiente (RIMSA), ISDE/FNOMCeO, Rome, Italy

Paolo Lauriola

Association of the chronically ill and rare patients, Cittadinazattiva APS, Rome, Italy

Tiziana Nicoletti

Study Center KOS-Science, Art, Society, Rome, Italy

Domenica Taruscio, Giovanni Taruscio & Alberto Mantovani

You can also search for this author in PubMed   Google Scholar

Contributions

EB coordinated the study; DT, GT, and AM conceived the study, RA, and LPN participated in its design; JP and PL collected data, TN and EB carried out the literature research. All the authors read and approved the final manuscript.

Corresponding author

Correspondence to Elena Bozzola .

Ethics declarations

Ethics approval and consent to participate, consent for publication, competing interests.

EB is the Associate Editor for IJP.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Bozzola, E., Agostiniani, R., Pacifici Noja, L. et al. The impact of indoor air pollution on children’s health and well-being: the experts’ consensus. Ital J Pediatr 50 , 69 (2024). https://doi.org/10.1186/s13052-024-01631-y

Download citation

Received : 05 January 2024

Accepted : 13 March 2024

Published : 14 April 2024

DOI : https://doi.org/10.1186/s13052-024-01631-y

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Indoor environment
• Environment and health
• Indoor air pollution
• Risk analysis
• Risk reduction

Italian Journal of Pediatrics

ISSN: 1824-7288

• Submission enquiries: Access here and click Contact Us
• General enquiries: [email protected]

An official website of the United States government

Here’s how you know

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

JavaScript appears to be disabled on this computer. Please click here to see any active alerts .

• Science & Case Studies
• Where the Rubber Meets the Road: Opportunities to Address Tire Wear Particles in Waterways (2023)

Report on Priority Microplastics Research Needs: Update to the 2017 Microplastics Expert Workshop

• Microplastics Expert Workshop Report  (2017)

State of the Science White Paper: A Summary of the Effects of Plastics Pollution on Aquatic Life and Aquatic-Dependent Wildlife

• Summary of Expert Discussion Forum on Possible Human Health Risks from Microplastics in the Marine Environment

Tern Island Preliminary Assessment and Technical Support Document

EPA conducts analysis and research to address important issues related to the potential health, ecological, and socio-economic impacts of trash and debris in the aquatic environment.

Where the Rubber Meets the Road: Opportunities to Address Tire Wear Particles in Waterways 

EPA’s Trash Free Waters (TFW) program announces the publication of  “Where the Rubber Meets the Road: Opportunities to Address Tire Wear Particles in Waterways.”  Tire wear particles as a pollutant in waterways is a relatively new field of study without standardized terminology, assessment methodologies, or established solutions. The emergence of tire wear particles as a significant category of microplastics found in waterways prompted EPA to convene stakeholders in two roundtable discussions in Spring 2022 to facilitate shared learning about the challenges of addressing the problem of tire wear particle pollution. Stakeholders represented diverse perspectives on the nature of the problem and how to effectively address it. The roundtables provided a forum for discussion among participants without committing to a specific course of action. Participants discussed a set of questions aimed at understanding the barriers to and opportunities for managing tire wear particles in waterways. This brief report summarizes the roundtable discussions. In producing it, EPA seeks to share the challenges and potential solutions discussed during the roundtables, in order to inform the public and broaden the community engaged in addressing tire wear particle pollution.

• View the Report:  Where the Rubber Meets the Road (pdf) (835 KB, April 2023, EPA-830-S-23-001)

In June 2017, the U.S. Environmental Protection Agency (EPA) Trash Free Waters Program convened a workshop that brought together subject matter experts (SME) in the fields of environmental monitoring, waste management, toxicology, ecological assessments, and human health assessments to discuss and summarize the risks posed by microplastics to ecological and human health (See "Microplastics Expert Workshop Report" below). The resulting workshop report outlined priority scientific information needs within four broad categories of research: Field and analytical methods; sources, transport, and fate; ecological assessments; and human health assessments.

The EPA Trash Free Waters Program has updated the 2017 Microplastics Expert Workshop (MEW) report to assist the scientific research and funding communities in identifying information gaps and emerging areas of interest within microplastics research. This report  includes a status update on the state of the science for each of the four categories listed above, informed by conversations with SMEs and a targeted review of the peer-reviewed literature.

• View the Report: A Trash Free Waters Report on Priority Microplastics Research Needs: Update to the 2017 Microplastics Expert Workshop (pdf) (2.1 MB, December 2021, EPA-842-R-21-005)

Microplastics Expert Workshop Report

The EPA Trash Free Waters program convened a Microplastics Expert Workshop (MEW) on June 28-29, 2017 to identify and prioritize the scientific information needed to understand the risks posed by microplastics to human and ecological health. The workshop gave priority to gaining greater understanding of these risks, while recognizing that there are many research gaps needing to be addressed and scientific uncertainties existing around microplastics risk management.  The workshop participants adopted a risk assessment-based approach and addressed four major topics: 1) microplastics methods, including deficits and needs; 2) microplastics sources, transport and fate; and 3) the ecological and 4) human health risks of microplastics exposure.  Workshop participants recommended developed detailed conceptual models to illustrate the fate of microplastics from source to receptor and assess the ecological and human health risks of microplastics, the degree to which information is available for each, and the interconnections among these uncertainties.  The expert panelists did not provide recommendations for specific regulatory or non-regulatory actions to be taken. This document presents a summary of the expert panel discussion.

• View the Report

Plastics have become a pervasive problem in oceans, coasts, and inland watersheds. Recent estimates suggest that 4.8 to 12.7 million metric tons of plastic waste entered the global marine environment in 2010. Areas of accumulation of plastic debris include enclosed basins, ocean gyres, and bottom sediments. Plastics in the aquatic environment primarily originate from land-based sources such as littering and wind-blown debris, though plastic debris from fishing activities may be a key source in some areas. Plastic particles are generally the most abundant type of debris encountered in the marine environment, with estimates suggesting that 60% to 80% of marine debris is plastic, and more than 90% of all floating debris particles are plastic. This document is a state-of-the-science review – one that summarizes available scientific information on the effects of chemicals associated with plastic pollution and their potential impacts on aquatic life and aquatic-dependent wildlife.

Summary of Expert Discussion Forum on Possible Human Health Risks from Microplastics in the Marine Environment

The EPA Trash Free Waters program convened a panel of scientific experts on April 23, 2014. The purpose of the forum was to discuss available data and studies on the issue of possible human health risks from microplastics in the marine environment. The participating subject matter experts were asked to provide insights on the current scientific basis for determining human health risks, based on a review of scientific research done to date. The experts also were asked to identify data gaps and make suggestions for further study. The expert panelists did not provide recommendations for specific regulatory or non-regulatory actions to be taken. This document presents a summary of the expert panel discussion.

In September 2014, EPA and the U.S. Fish and Wildlife Service released an initial assessment of contamination at Tern Island, a remote island in the chain of Northwestern Hawaiian Islands (NWHI). The results show that there have been releases of hazardous substances such as polychlorinated biphenyls (PCBs) and lead from military wastes buried on the island between World War II and 1979, and further action is warranted.

• View the report
• Trash Free Waters Home
• Learn About Aquatic Trash
• What EPA is Doing
• What You Can Do
• Best Management Practices & Tools
• Webinar Library
• Trash Free Waters Article Series
• 'The Flow' Newsletter Archive
• 'The Rapids' Email Archive

Air Pollution Case studies

Documentation of case studies on air pollution from 50+ countries.

At Oizom, our vision is to empower various industries with highly scalable data-driven solutions for a sustainable future. Explore how Oizom Environmental Monitoring Solutions enable the Smart City Authorities, Real Estate Organizations, Airports, WWTPs, and Landfills to tackle the global menace of pollution. Here are some air pollution case studies.

Stay updated on latest case studies on air pollution

Latest Air Pollution Case Studies

Raymond Realty Enhancing Environmental Safety in Construction with Oizom’s AQBot

Raymond Realty Enhancing Environmental Safety in Construction with Oizom’s AQBot By choosing Oizom’s AQBot for PM monitoring, Raymond Realty, a leading real estate builder and construction company, is successfully addressing

Continuously Monitoring Dust at Lokhandwala Developers with Oizom’s AQBot

Continuously Monitoring Dust at Lokhandwala Developers with Oizom’s AQBot Oizom, with its proven track record of delivering high-quality and accurate environmental monitoring systems, was chosen by Lokhandwala Developers to solve

Empowering Amara Raja with Air Quality Monitoring Solutions

Empowering Amara Raja with Air Quality Monitoring Solutions Amara Raja Energy & Mobility Limited transformed its production environment with Oizom’s innovative real-time air quality monitoring solution. The solutions they implemented

Combating Air Pollution in PT Kawasan Berikat Nusantara Industrial Zones with Oizom

Combating Air Pollution in PT Kawasan Berikat Nusantara Industrial Zones with Oizom With Oizom’s Polludrone, PT Kawasan Berikat Nusantara combat Air Pollution in the Industrial Zones, as there is a

Reliance Chemical Products Ltd. chooses Oizom to achieve operational excellence with an advanced air monitoring system

Reliance Chemical Products Ltd. chooses Oizom to achieve operational excellence with an advanced air monitoring system Reliance Chemical Products Ltd. chooses Oizom to monitor SO2 and CH4 concentration on their

Enhancing Safety and Efficiency in Skanska’s Tunnel Construction

Enhancing Safety and Efficiency in Skanska’s Tunnel Construction In a Norwegian tunnel project, Skanska improved safety and efficiency using a specialised instrument for air quality monitoring, enabling better explosive use

Monitoring air pollution and mitigation for workplace safety at a Cement Factory in India

Monitoring air pollution and mitigation for workplace safety at a Cement Factory in India Oizom’s Dustroids and Devic Earth’s Pure Skies technologies were deployed at cement factory for monitoring air

Odour and air quality monitoring in Richards Bay Coal Terminal

Odour and air quality monitoring in Richards Bay Coal Terminal Oizom has set up 3 units of Odosense and 1 unit of Polludrone in the Richards Bay Coal Terminal for

Real-time Air Quality Monitoring in Mahavir Coal Washery, India

Real-time Air Quality Monitoring in Mahavir Coal Washery, India Oizom is monitoring the air pollution levels in the Mahavir Coal Washeries by installing an Air Quality monitoring system – Polludrone.

Bioreactor Landfill odour monitoring in the Republic of Croatia

A Bioreactor Landfill in Croatia installed Oizom’s odour monitoring system, Odosense Smart to monitor odour and other air pollutants. Download Case study Republic of Croatia March 2022 Odour Monitoring County

Air Pollution Monitoring for Davangere Smart City

Case study on the city-wide implementation of Air Pollution Monitoring System for Smart City Davangere, Karnataka. Download Case study Davangere, Karnataka, India May 2019 Smart City Monitoring Ionnix Smart Systems

Monitoring odour levels in Dubai’s Waste Water Treatment Plant

Monitoring odour levels in Dubai’s Waste Water Treatment Plant A world-class mining company chose Dustroid to maintain occupational health and safety by dust monitoring in gold undermine. Download Case study

Monitoring Weather in Adani Dighi Port, Maharashtra

Adani Dighi Port in Maharashtra is monitoring the weather by using Oizom’s Weather Monitoring Station – Weathercom. Download Case study Dighi Port, Maharashtra November 2021 Weather Monitoring Pollucon Laboratories Pvt.

Ensuring Workers’ safety by dust monitoring in the Red Sea Airport

Ensuring Workers’ safety by dust monitoring in the Red Sea Airport Dust monitoring in the Red Sea luxury vacation project by the cost of Saudi Arabia is being monitored by

Flood and weather monitoring in Colombia

Oizom is monitoring rainfall and flood levels in North Colombia on a real-time basis to safeguard civilians from the same. Download Case study Colombia February 2022 Flood Monitoring Unidad Nacional

Monitoring dust for one of the largest coal mines in the world

Monitoring dust for one of the largest coal mines in the world Oizom is monitoring the Dust and other air pollutant emissions from one of the largest Coal mines in

Alerting Authorities of sandstorm and monitoring air quality in a Saudi Arabian mining site

Alerting Authorities of sandstorm and monitoring air quality in a Saudi Arabian mining site Monitoring air quality and alerting the authorities of the sandstorms in a Saudi Arabian mining site

Detecting Hydrogen Chloride (HCl) Fumes in Godrej Manufacturing Unit

Oizom’s Polludrone is monitoring Hydrogen Chloride (HCl) fumes and other air pollutants in Godrej & Boyce Mfg. Co. Ltd. Download Case study Mumbai October 2021 Air Quality Monitoring TechnoValue Solutions

Our Contribution in Cost-Effective Air Pollution Monitoring

Oizom has successfully excelled at developing wholesome ambient air quality measurement systems. Intelligent IoT-driven devices help in taking the first step in air pollution mitigation. Our outdoor air quality monitors are helping from providing the government with efficient air quality monitors for Smart City Development to prioritizing the need for Industrial Hygiene. Our case studies on air pollution monitoring showcase the impact of deploying sensor-based ambient air quality monitoring systems.

We cater solutions to Smart City Authorities, Real Estate Organizations, Airports, WWTPs, landfills, and various other communities that are user-friendly and devices that are compact and easy to install/work with. Some air pollution case studies prove how these solutions have made customers feel healthier, safer, and increasingly sustainable.

Think We Can Help You?

• Get In Touch
• Request Quote

Stay updated on air quality monitoring news & updates

Sign up for our newsletter to stay updated with industry news,  air quality monitoring trends, new product releases, and company updates.

Oizom offers Environmental IoT and Environmental Ai solutions for a sustainable future.

HB9, Savoie Technolac, Le Bourget du Lac – France [email protected]

• Urban air quality monitoring
• Odour monitoring
• Air quality monitoring for industries
• Air quality research

Quick Links

• About Oizom
• Our Technology
• Knowledge Bank
• Events & Webinars
• 2023 © OIZOM INSTRUMENTS PVT. LTD.
• Privacy Policy
• Cookie Policy
• Terms Of Use

Privacy Overview

Source analysis of chlorine in municipal solid waste under waste classification: a case study of Hangzhou, China

• Research Article
• Published: 16 April 2024

Cite this article

• Yuyang Long 1 ,
• Ying Hu 1 ,
• Dongyun Liu 1 ,
• Dongsheng Shen 1 &
• Foquan Gu 1  

26 Accesses

Explore all metrics

Inorganic chlorine is susceptible to water and soil salinization due to its non-degradability and high mobility. To clarify the environmental risks associated with the active inorganic chlorine in municipal solid waste (MSW), the specific characteristics and contributions of inorganic chlorine in different MSW categories were investigated in this study. MSW samples were collected from eight representative waste classification residential areas in Hangzhou, China. It was found that the inorganic chlorine content in different MSW categories varied significantly (0–113 mg/g). Perishable waste, paper, and plastic were found to be the main sources of inorganic chlorine in MSW. A four-category classification system was used to quantify the contribution of inorganic chlorine from each waste category. It was found that the misclassification of inorganic chlorine contributions from perishable waste and other waste accounted for 51.96% and 48.04%, respectively. However, when correctly classified into the four-category system, their contributions were reduced to 67.14% and 30.65%, respectively. Therefore, MSW classification showed a significant reduction in the overall contribution of inorganic chlorine. The misclassification reduces the contribution of inorganic chlorine to 48.04%, while correct classification increases the reduction to 69.35%.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Similar content being viewed by others

A review of municipal solid waste in China: characteristics, compositions, influential factors and treatment technologies

Yanli Zhu, Youxian Zhang, … Xuepeng Kong

Assessment of the leachate quality from municipal solid waste landfill in Lebanon

Rana Sawaya, Jalal Halwani, … Nada Nehme

Pollution Indices and Potential Ecological Risks of Heavy Metals in the Soil: A Case Study of Municipal Wastes Site in Ondo State, Southwestern, Nigeria

Lasun T. Ogundele, Patrick O. Ayeku, … Isaiah A. Adejoro

Bian R, Chen J, Zhang T, Gao C, Niu Y, Sun Y, Zhan M, Zhao F, Zhang G (2022) Influence of the classification of municipal solid wastes on the reduction of greenhouse gas emissions: a case study of Qingdao City, China. J Clean Prod 376:134275. https://doi.org/10.1016/j.jclepro.2022.134275

Article   CAS   Google Scholar  

Cai Z, Du B, Dai X, Wang T, Wang J, Zhang Y (2023) Coupling of alkaline and mechanical modified fly ash for HCl and SO 2 removal in the municipal solid waste incineration plant. Fuel 346:128354. https://doi.org/10.1016/j.fuel.2023.128354

Cheng S, Ding X, Dong X, Zhang M, Tian X, Liu Y, Huang Y, Jin B (2023) Immigration, transformation, and emission control of sulfur and nitrogen during gasification of MSW: fundamental and engineering review. Carbon Resour Convers 6:184–204. https://doi.org/10.1016/j.crcon.2023.03.003

Deng Y, Chen N, Feng C, Chen F, Wang H, Kuang P, Feng Z, Liu T, Gao Y, Hu W (2019) Treatment of organic wastewater containing nitrogen and chlorine by combinatorial electrochemical system: taking biologically treated landfill leachate treatment as an example. Chem Eng J 364:349–360. https://doi.org/10.1016/j.cej.2019.01.176

Gu B, Jiang S, Wang H, Wang Z, Jia R, Yang J, He S, Cheng R (2017) Characterization, quantification and management of China’s municipal solid waste in spatiotemporal distributions: a review. Waste Manag 61:67–77. https://doi.org/10.1016/j.wasman.2016.11.039

Article   Google Scholar  

Honma S, Hu J (2021) Cost efficiency of recycling and waste disposal in Japan. J Clean Prod 284:125274. https://doi.org/10.1016/j.jclepro.2020.125274

Kassman H, Pettersson J, Steenari BM, Åmand LE (2013) Two strategies to reduce gaseous KCl and chlorine in deposits during biomass combustion — injection of ammonium sulphate and co-combustion with peat. Fuel Process Technol 105:170–180. https://doi.org/10.1016/j.fuproc.2011.06.025

Kruta de Araujo NC, Sato T (2018) A descriptive study of work ability and health problems among Brazilian recyclable waste pickers. J Commun Health 43:366–371. https://doi.org/10.1007/s10900-017-0432-6

Li H, Liu H, Huang Y, Chen X, Zhang X, Li J, Xu L, Yao H (2024a) Mechanism of coupling corrosion caused by flue gas and deposits in municipal solid waste incinerator: roles of H 2 O(g), HCl, and SO 2 . Corros Sci 231:111933. https://doi.org/10.1016/j.corsci.2024.111933

Li S, Zhang M, Hu H, Guo G, Gong L, Dong L, Xu S, Yao H (2024b) Fate of sulfur and chlorine during co-incineration of municipal solid waste and industrial organic solid waste. Sci Total Environ 920:171040. https://doi.org/10.1016/j.scitotenv.2024.171040

Liu Y, Wang J (2023) Spatiotemporal patterns and drivers of carbon emissions from municipal solid waste treatment in China. Waste Manag 168:1–13. https://doi.org/10.1016/j.wasman.2023.05.043

Liu Y, Xing P, Liu J (2017) Environmental performance evaluation of different municipal solid waste management scenarios in China. Resour Conserv Recycl 125:98–106. https://doi.org/10.1016/j.resconrec.2017.06.005

Liu B, Han Z, Liang X (2023) Dioxin emissions from municipal solid waste incineration in the context of waste classification policy. Atmos Pollut Res 14:101842. https://doi.org/10.1016/j.apr.2023.10184

Long Y, Shen D, Wang H, Lu W, Zhao Y (2011) Heavy metal source analysis in municipal solid waste (MSW): case study on Cu and Zn. J Hazard Mater 186:1082–1087. https://doi.org/10.1016/j.jhazmat.2010.11.106

Long Y, Liu D, Xu J, Fang Y, Du Y, Shen D (2018) Release behavior of chloride from MSW landfill simulation reactors with different operation modes. Waste Manag 77:350–355. https://doi.org/10.1016/j.wasman.2018.04.018

Lv L, Sun P, Gu Z, Du H, Pang X, Tao X, Xu R, Xu L (2009) Removal of chloride ion from aqueous solution by ZnAl-NO 3 layered double hydroxides as anion-exchanger. J Hazard Mater 161:1444–1449. https://doi.org/10.1016/j.jhazmat.2008.04.114

Lv J, Dong H, Geng Y, Li H (2020) Optimization of recyclable MSW recycling network: a Chinese case of Shanghai. Waste Manag 102:763–772. https://doi.org/10.1016/j.wasman.2019.11.041

Ma W, Wenga T, Frandsen FJ, Yan B, Chen G (2020) The fate of chlorine during MSW incineration: vaporization, transformation, deposition, corrosion and remedies. Prog Energy Combust Sci 76:100789. https://doi.org/10.1016/j.pecs.2019.100789

McSorley K, Rutter A, Cumming R, Zeeb BA (2016) Phytoextraction of chloride from a cement kiln dust (CKD) contaminated landfill with Phragmites australis. Waste Manag 51:111–118. https://doi.org/10.1016/j.wasman.2015.11.009

Shan L, Tian S, Hu Q (2016) Effect of deicing chloride salts on roadside plants and soil. Saf Environ Eng 23:89–95. https://doi.org/10.13578/j.cnki.issn.1671-1556.2016.03.015

Song Y, Xian X, Zhang C, Zhu F, Yu B, Liu J (2023) Residual municipal solid waste to energy under carbon neutrality: challenges and perspectives for China. Resour Conserv Recycl 198:107177. https://doi.org/10.1016/j.resconrec.2023.107177

Tai J, Zhang W, Che Y, Feng D (2011) Municipal solid waste source-separated collection in China: a comparative analysis. Waste Manag 31:1673–1682. https://doi.org/10.1016/j.wasman.2011.03.014

Tang L, Guo J, Wan R, Jia M, Qu J, Li L, Bo X (2023) Air pollutant emissions and reduction potentials from municipal solid waste incineration in China. Environ Pollut 319:121021. https://doi.org/10.1016/j.envpol.2023.121021

Teakle NL, Tyerman SD (2010) Mechanisms of Cl-transport contributing to salt tolerance. Plant Cell Environ 33:566–589. https://doi.org/10.1111/j.1365-3040.2009.02060.x

Vehlow J (1996) Municipal solid waste management in Germany. Waste Manag 16:367–374. https://doi.org/10.1016/S0956-053X(96)00081-5

Yang N, Zhang H, Chen M, Shao L, He P (2012) Greenhouse gas emissions from MSW incineration in China: impacts of waste characteristics and energy recovery. Waste Manag 32:2552–2560. https://doi.org/10.1016/j.wasman.2012.06.008

Zhao F, Bian R, Zhang T, Fang X, Chai X, Xin M, Li W, Sun Y, Yuan L, Chen J, Lin X, Liu L (2022) Characteristics of polychlorinated dibenzodioxins/dibenzofurans from a full-scale municipal solid waste (MSW) incinerator in China by MSW classification. Process Saf Environ 161:50–57. https://doi.org/10.1016/j.psep.2022.03.012

Zhou H, Long Y, Meng A, Li Q, Zhang Y (2015) Thermogravimetric characteristics of typical municipal solid waste fractions during co-pyrolysis. Waste Manag 38:194–200. https://doi.org/10.1016/j.wasman.2014.09.027

Download references

This work was partially supported by the Scientific Research Project of Zhejiang Provincial Department of Education (Y202147303).

Author information

Authors and affiliations.

School of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Engineering Research Center of Non-Ferrous Metal Waste Recycling, Zhejiang Gongshang University, Hangzhou, 310012, Zhejiang, China

Yuyang Long, Ying Hu, Dongyun Liu, Dongsheng Shen & Foquan Gu

You can also search for this author in PubMed   Google Scholar

Contributions

Yuyang Long: project administration, supervision, writing—review and editing; Ying Hu: investigation, data curation, visualization; Dongyun Liu: data curation, visualization; Dongsheng Shen: supervision, resources; Foquan Gu: writing—original draft, writing—review and editing, formal analysis, validation.

Corresponding author

Correspondence to Foquan Gu .

Ethics declarations

Ethics approval.

Not applicable.

Consent to participate

Consent for publication, conflict of interest.

The authors declare no competing interests.

Additional information

Responsible Editor: Xianliang Yi

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Long, Y., Hu, Y., Liu, D. et al. Source analysis of chlorine in municipal solid waste under waste classification: a case study of Hangzhou, China. Environ Sci Pollut Res (2024). https://doi.org/10.1007/s11356-024-33243-8

Download citation

Received : 29 September 2023

Accepted : 03 April 2024

Published : 16 April 2024

DOI : https://doi.org/10.1007/s11356-024-33243-8

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Classification
• Find a journal
• Publish with us
• Track your research