Air Quality in Metropolitan Areas and Megacities

A special issue of Atmosphere (ISSN 2073-4433). This special issue belongs to the section "Air Quality".

Deadline for manuscript submissions: 26 July 2024 | Viewed by 12524

Special Issue Editors


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Guest Editor
Department of Environmental Health, School of Public Health, University of São Paulo, Av. Dr. Arnaldo, 715, São Paulo 05508-070, Brazil
Interests: aerosols; air pollution; air particulate matter; air quality; tropospheric ozone; VOCs; Health Assessment; elemental analysis

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Guest Editor
Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais. Av. Antônio Carlos, 6.627, Belo Horizonte 31270-901, MG, Brazil
Interests: air pollution; air particulate matter; air quality; air quality modeling; air pollution control and modeling applications
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Center for Climate and Resilience Research, Department of Geophysics, Faculty of Physical and Mathematical Sciences, University of Chile. Blanco Encalada 2002, 4to piso, Santiago, Chile
Interests: ozone trends; volatile organic compounds; air quality; urban resilience

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Guest Editor

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Guest Editor
Department of Chemical and Environmental Engineering, Universidad Nacional de Colombia, Carrera 45 26-86, Colombia
Interests: air pollution; PM; source apportionment; atmospheric emission

Special Issue Information

Dear Colleagues,

Air pollution is the world’s single greatest environmental risk to health. Some 6.5 million people across the world die prematurely every year from exposure to outdoor and indoor air pollution, and nine out of ten people breathe outdoor air polluted beyond acceptable WHO guidelines levels.

Megacities (metropolitan areas with populations over 10 million) present a major global environmental challenge. Rapid population growth, unsustainable urban development, and increased energy demand by transportation, industrial, commercial, and residential activities, have led to large amounts of emissions to the atmosphere that subject the residents to the health risks associated with harmful pollutants, and impose heavy economic and social costs.

The aim of this Special Issue is to present original research articles and reviews in assessing air pollution in metropolitan areas and megacities, including both experimental and monitoring studies and mathematical/numerical modeling studies. Topics to be covered include gases pollutants and urban aerosol observations, including particulate matter chemical characterization and human exposure assessment.

Dr. Thiago Nogueira
Dr. Taciana Toledo De Almeida Albuquerque
Dr. Rodrigo J. Seguel
Dr. Manousos Ioannis Manousakas
Dr. Néstor Y. Rojas
Guest Editors

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Published Papers (7 papers)

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Research

15 pages, 5251 KiB  
Article
Use of Low-Cost Sensors for Environmental Health Surveillance: Wildfire-Related Particulate Matter Detection in Brasília, Brazil
by Patrick Connerton, Thiago Nogueira, Prashant Kumar and Helena Ribeiro
Atmosphere 2023, 14(12), 1796; https://doi.org/10.3390/atmos14121796 - 8 Dec 2023
Cited by 1 | Viewed by 1303
Abstract
Ambient air quality is the most important environmental factor affecting human health, estimated by the WHO to be responsible for 4.2 million deaths annually. Having timely estimates for air quality is critical for implementing public policies that can limit anthropogenic emissions, reduce human [...] Read more.
Ambient air quality is the most important environmental factor affecting human health, estimated by the WHO to be responsible for 4.2 million deaths annually. Having timely estimates for air quality is critical for implementing public policies that can limit anthropogenic emissions, reduce human exposure and allow for preparation and interventions in the health sector. In Brazil, wildfires constitute an important source of particulate matter emission, particularly in the country’s northern and midwestern regions, areas that are under-served in terms of air quality monitoring infrastructure. In the absence of regulatory-grade monitoring networks, low-cost sensors offer a viable alternative for generating real-time, publicly available estimates of pollutant concentrations. Here, we examine data from two low-cost sensors deployed in Brasília, in the Federal District of Brazil, during the 2022 wildfire season and use NOAA’s HYSPLIT model to investigate the origin of a particulate matter peak detected by the sensors. There was high agreeability of the data from the two sensors, with the raw values showing that daily average PM2.5 concentrations reached peak values of 46 µg/m3 and 43 µg/m3 at the school and park sites, respectively. This study demonstrates the value of low-cost sensors and their possible application in real-time scenarios for environmental health surveillance purposes. Full article
(This article belongs to the Special Issue Air Quality in Metropolitan Areas and Megacities)
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21 pages, 4859 KiB  
Article
Air Quality Characterization and Trend Analysis in a Brazilian Industrialized Metropolitan Area in the Period from 1995 to 2022
by Amanda Karine Chaves Ribeiro, Elson Silva Galvão and Taciana Toledo de Almeida Albuquerque
Atmosphere 2023, 14(12), 1792; https://doi.org/10.3390/atmos14121792 - 6 Dec 2023
Cited by 1 | Viewed by 867
Abstract
The Brazilian population grew approximately 9% from 2006 to 2016, and the number of deaths caused by air pollution increased by 14% in Brazil in the same period. Facing the lack of studies on air quality in the Metropolitan Area of Belo Horizonte [...] Read more.
The Brazilian population grew approximately 9% from 2006 to 2016, and the number of deaths caused by air pollution increased by 14% in Brazil in the same period. Facing the lack of studies on air quality in the Metropolitan Area of Belo Horizonte (MABH)—the third most populous Brazilian metropolitan area—this study aimed to investigate the air quality and the trends of air pollutant concentrations in the MABH between 1995 and 2022, using data from the air quality monitoring network. The methodology consisted of checking MABHs air quality trends following the WHO air quality guidelines. The Mann–Kendall test was used to check statistically for the possibility of tendencies. The results showed a trend of stability in the concentrations of air pollutants in the MABH without any trend of improvement or worsening. However, the time series of the MABH exposed the challenge of ensuring better air quality that protects human health. Furthermore, the results reinforced the importance of focusing on pollutant sources and exposed the need for improvements in air quality management. Thus, it is essential to reverse the current dismantling scenario of the public environmental agencies in Brazil. Full article
(This article belongs to the Special Issue Air Quality in Metropolitan Areas and Megacities)
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16 pages, 8547 KiB  
Article
Spatiotemporal Variability of Urban Air Pollution in Bucharest City
by Alexandru Ilie, Jeni Vasilescu, Camelia Talianu, Cristian Iojă and Anca Nemuc
Atmosphere 2023, 14(12), 1759; https://doi.org/10.3390/atmos14121759 - 29 Nov 2023
Viewed by 961
Abstract
Urban air pollution is one of the major challenges that cities around the world face. Particulate matter (PM), nitrogen dioxide (NO2), volatile organic compounds (VOCs), and other pollutants are many times over the recommended airborne exposure, generating a strong impact on [...] Read more.
Urban air pollution is one of the major challenges that cities around the world face. Particulate matter (PM), nitrogen dioxide (NO2), volatile organic compounds (VOCs), and other pollutants are many times over the recommended airborne exposure, generating a strong impact on human health and city well-being. Considering Bucharest as a case study, this study aimed to investigate the patterns of particulate matter and nitrogen dioxide concentrations. Multiyear data from the Romanian National Air Quality Monitoring Network were used to investigate spatial and temporal variability. All air pollutants presented a typical bimodal trend during the day, with specific double peaks corresponding to the morning rush hours and nighttime. Spatial variability in NO2 concentrations was observed, with almost double the concentration values in the city center during midday compared with those for the background and industrial areas. A weekly pattern of PM was noticed, with lower concentrations during the weekends in comparison with those during weekdays, more pronounced in the case of PM10 compared with the case of PM2.5. The fine particle fraction presented monthly and seasonal variability, with higher levels during the cold months compared with the warm months, mainly corresponding to the increased household heating. The estimated proportion of mortality attributable to annual exposure to an air PM2.5 above 5 μg/m3 in Bucharest ranged between 7.55% and 8.26%, with the maximum from 2021. By contrast, the estimated proportion of mortality attributable to PM10 and NO2 above 10 μg/m3 was significantly lower, with values around 4%. The results are useful in supporting environmental planning measures to decrease urban air pollution. Full article
(This article belongs to the Special Issue Air Quality in Metropolitan Areas and Megacities)
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17 pages, 1048 KiB  
Article
An MCDM Approach to Analytically Identify the Air Pollutants’ Impact on Health
by Rashmi Bhardwaj and Shanky Garg
Atmosphere 2023, 14(6), 909; https://doi.org/10.3390/atmos14060909 - 23 May 2023
Cited by 2 | Viewed by 1339
Abstract
Air pollution is one of the deadliest and most important concerns of our era, and it not only impacts our environment but also our health. The consequences of poor air quality are not limited to just our lungs or our heart but also [...] Read more.
Air pollution is one of the deadliest and most important concerns of our era, and it not only impacts our environment but also our health. The consequences of poor air quality are not limited to just our lungs or our heart but also our brain and resulting in increased mortality rate of many countries every year. There are many effluents/pollutants present in the air that are harmful and cause diseases in humans which eventually lead to an increase in morbidity and mortality. Therefore, there is a need to identify those factors and evaluate the effect of pollution caused by air on the health of humans which is a prerequisite for the implementation of policies in preventing pollution. In this study, we model and evaluate the harmful impact of pollution caused by air on the health of humans by using a multi-criteria decision-making approach (MCDM). We have proposed a novel coupled model of the double modified (criteria importance through intercriteria correlation) CRITIC—technique for order of preference by similarity to ideal solution (TOPSIS) method (DMCTM) to identify and evaluate the factors of air pollution and its effect on health which overcome the disadvantage of bias while collecting the subjective data in the traditional TOPSIS method. To get a clear view of the framework proposed, a case study is conducted based on the methodology proposed in which we find that Xinxiang is the most polluted city in China among the five studied cities with SO2 as the major contributor, and the city experienced more pollution levels in 2022 and least in 2016, whereas there is a slight fluctuation in life expectancy with air pollution in the years 2015 and 2023. Full article
(This article belongs to the Special Issue Air Quality in Metropolitan Areas and Megacities)
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19 pages, 5365 KiB  
Article
Future Ozone Levels Responses to Changes in Meteorological Conditions under RCP 4.5 and RCP 8.5 Scenarios over São Paulo, Brazil
by Alejandro H. Delgado Peralta, Mario Gavidia-Calderón and Maria de Fatima Andrade
Atmosphere 2023, 14(4), 626; https://doi.org/10.3390/atmos14040626 - 26 Mar 2023
Cited by 1 | Viewed by 1666
Abstract
Since the implementation of emission control policies in 1983, the Metropolitan Area of São Paulo (MASP) has experienced a significant decrease in the annual mean concentration of air pollutants, except for ozone, which has remained relatively stable. This work analyzes the future impact [...] Read more.
Since the implementation of emission control policies in 1983, the Metropolitan Area of São Paulo (MASP) has experienced a significant decrease in the annual mean concentration of air pollutants, except for ozone, which has remained relatively stable. This work analyzes the future impact on surface ozone formation in the MASP caused by changes in atmospheric conditions. The authors performed air quality simulations using the weather research and forecasting with chemistry (WRF-Chem) model under two representative concentration pathway (RCP) atmospheric conditions. A base case simulation from September and October 2018 was compared to scenarios for the same months in 2030, using the same anthropogenic emissions. Results show an average increase in peak ozone concentrations (0.43% for RCP 4.5 and 5.92% for RCP 8.5) with variations depending on the month and location. However, under the RCP 4.5 scenario, peak ozone concentrations in October were higher in urban areas than under the RCP 8.5. These outcomes can assist decision-makers in understanding the potential future impacts of high ozone formation, which has historically occurred in September and October in São Paulo by considering the effects of changing meteorological conditions, such as increased temperatures, higher surface radiation, and reduced cloudiness. Full article
(This article belongs to the Special Issue Air Quality in Metropolitan Areas and Megacities)
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14 pages, 2136 KiB  
Article
Emission Source Areas of Fine Particulate Matter (PM2.5) in Ho Chi Minh City, Vietnam
by Tuyet Nam Thi Nguyen, Nguyen Xuan Du and Nguyen Thi Hoa
Atmosphere 2023, 14(3), 579; https://doi.org/10.3390/atmos14030579 - 17 Mar 2023
Cited by 4 | Viewed by 3489
Abstract
This study aims to determine emission source areas of fine particulate matter (PM2.5) in Ho Chi Minh (HCM) City, Vietnam, using a conditional bivariate probability function (CBPF) and hybrid receptor models, including three-dimensional potential source contribution function (3D-PSCF) and concentration-weighted trajectory [...] Read more.
This study aims to determine emission source areas of fine particulate matter (PM2.5) in Ho Chi Minh (HCM) City, Vietnam, using a conditional bivariate probability function (CBPF) and hybrid receptor models, including three-dimensional potential source contribution function (3D-PSCF) and concentration-weighted trajectory (3D-CWT), considering latitudes, longitudes, and height of trajectory segments. Uncertainties of the CBPF and 3D-PSCF/3D-CWT were evaluated based on the 95th confidence intervals and 95% confidence levels, respectively. For the local scale, PM2.5 in HCM City was primarily emitted from shallow or common ground sources (e.g., vehicle emissions) throughout the year. Regarding non-local source areas, PM2.5 in HCM City is contributed by those originated from the East Sea (e.g., shipping emissions) and southeastern Vietnam (e.g., Binh Duong and Dong Nai provinces) having several industrial zones with PM2.5 emission sources, especially in the dry season (December to April of the following year). In the rainy season (May–November), PM2.5 derived from emission sources in the Mekong Delta (e.g., biomass burning) might be transported to HCM City. However, contribution of the non-local sources to PM2.5 pollution in HCM City during the rainy season is less important because of PM2.5 deposition stemmed from the high rainfall amount in this season. Full article
(This article belongs to the Special Issue Air Quality in Metropolitan Areas and Megacities)
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17 pages, 7295 KiB  
Article
Exploring Natural and Anthropogenic Drivers of PM2.5 Concentrations Based on Random Forest Model: Beijing–Tianjin–Hebei Urban Agglomeration, China
by Shasha Guo, Xiaoli Tao and Longwu Liang
Atmosphere 2023, 14(2), 381; https://doi.org/10.3390/atmos14020381 - 15 Feb 2023
Cited by 5 | Viewed by 1855
Abstract
PM2.5 is the key reason for the frequent occurrence of smog; therefore, identifying its key driving factors has far-reaching significance for the prevention and control of air pollution. Based on long-term remote sensing inversion of PM2.5 data, 21 driving factors in [...] Read more.
PM2.5 is the key reason for the frequent occurrence of smog; therefore, identifying its key driving factors has far-reaching significance for the prevention and control of air pollution. Based on long-term remote sensing inversion of PM2.5 data, 21 driving factors in the fields of nature and humanities were selected, and the random forest model was applied to study the influencing factors of PM2.5 concentration in the Beijing–Tianjin–Hebei urban agglomeration (BTH) from 2000 to 2016. The results indicate: (1) The main factors affecting PM2.5 concentration not only include natural factors such as sunshine hours (SSH), relative humidity (RHU), elevation (ELE), normalized difference vegetation index (NDVI), wind speed (WIN), average temperature (TEM), daily temperature range (TEMR), and precipitation (PRE), but also human factors such as urbanization rate (URB), total investment in fixed assets (INV), and the number of employees in the secondary industry (INDU); (2) The concentration of PM2.5 changed into an inverted S-shape with the increase in SSH and WIN, and into an S-shape with the increase in RHU, NDVI, TEM, PRS, URB and INV. As for ELE and TEMR, it fluctuated and decreased with the increase in ELE, while it increased and then decreased with the increase in TEMR. However, its change was less pronounced with the increase in PRE and INDU; (3) The influence of natural factors is higher than that of human factors, but the role of human factors has been continuously strengthened in recent years. The adjustment and control of PM2.5 pollution sources from the perspective of human factors will become an effective way to reduce PM2.5 concentrations in the BTH. Full article
(This article belongs to the Special Issue Air Quality in Metropolitan Areas and Megacities)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

  1. Title: Use of low-cost sensors for environmental health surveillance: wildfire-related particulate matter detection in Brasília, Brazil

 

Authors: Patrick Joseph Connerton1, Thiago Nogueira1, Prashant Kumar2, Helena Ribeiro1

  1. University of São Paulo, School of Public Health
  2. University of Surrey, Department of Civil and Environmental Engineering

 

Abstract: Ambient air quality is the most important environmental factor affecting human health, estimated by the WHO to be responsible for 4.2 million deaths annually. Having timely estimates for air quality is critical for implementing public policies that can limit anthropogenic emissions, reduce human exposure and allow for preparation and interventions in the health sector. In Brazil, wildfires constitute an important source of particulate matter emission, particularly in the North and Mid-West regions, areas that are underserved in terms of air quality monitoring infrastructure. In the absence of regulatory-grade monitoring networks, low-cost sensors offer a viable alternative for generating real-time, publicly-available estimates of pollutant concentrations. Here, we examine data from two low-cost sensors deployed in Brasília, in the Federal District of Brazil, during the 2022 wildfire season and use NOAA’s HYSPLIT model to investigate the origin of a particulate matter peak detected by the sensors. There was high agreeability of the data from the two sensors, which showed that daily average PM10 and PM2.5 concentrations reached peak values of 60 ug/m3 and 41 ug/m3, respectively. This study demonstrates the value of low cost sensors and their possible application in real-time scenarios for environmental health surveillance purposes. 

 

 

  1. Title: Air Quality in the Megacity of Belo Horizonte: Characterization, Trend Analysis and Future Perspectives

 

Authors: Amanda Karine Chaves Ribeiro¹, Elson Silva Galvão2,3, Taciana Toledo de Almeida Albuquerque1,2,4

¹ Programa de Pós-Graduação em Saneamento, Meio Ambiente e Recursos Hídricos, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627, 31270-901, Belo Horizonte, Brasil.

² Programa de Pós-Graduação em Engenharia Ambiental, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Vitória, Espírito Santo, Brasil.

3Departamento de Engenharia Ambiental, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Vitória, Espírito Santo, Brasil.

4Departamento de Engenharia Sanitária e Ambiental, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627, 31270-901, Belo Horizonte, Brasil

 

Abstract: This study aimed to investigate the air quality characterization and the trend of air pollutants concentrations in the Metropolitan Area of Belo Horizonte (MABH), the third most populous Brazilian metropolitan area. It created air quality trends using measurements from monitors located across the MABH from 1995 to 2021, using data on pollutants MP10, MP2,5, NO2, O3, SO2, and CO. The methodology consisted in checking the trend and the characterization of MABH's air quality following the World Health Organization (WHO) guidelines and interim targets. The results showed a trend of stability in the concentrations of air pollutants in the MABH, with no prospect of improvement or worsening. The Mann-Kendall test was used to check the possibility of tendency statistically. However, the historical characterization in the MABH exposed the region's challenge in ensuring good air quality that provides human health, with concentrations that remained higher than WHO guidelines. Furthermore, the results reinforced the importance of the industrial sector for air pollution in the MABH and exposed the need for improvement in air quality management. In this way, it is essential to reverse the current dismantling scenario of public environmental agencies.

 

 

  1. Title: Wind-Cluster Based Study of Interannual Variations in Air Quality in The City of Buenos Aires

 

Authors: Caterina Mosto, Andrea Pineda Rojas, Néstor Rojas

Department of Chemical and Environmental Engineering – Universidad Nacional de Colombia

 

Abstract: In this work, interannual variations in the concentration of nitrogen dioxide (NO2), carbon monoxide (CO), and particulate matter with diameters less than 10 mm (PM10) at the three air quality monitoring stations of the city of Buenos Aires are studied for the period 2010-2019. A simple statistical trend analysis is used, as well as a clustering based on the daily sequence of hourly wind. A significant decrease in the annual mean PM10 concentration of 1.6 mg/m3.yr is observed at the urban background station. Consistently, a reduction in the frequency of daily exceedances of the World Health Organization (WHO) air quality guideline (AQG) level of 1.6 %/yr is also found. Annual and daily NO2 concentrations are frequently above the WHO AQG levels at the three sites, presenting positive trends that could become statistically significant in the future as new data is made available. When the daily hourly wind sequence is used as a classification variable, marked differences in pollutant concentration levels are observed with different wind patterns. While in general these differences are maintained over the years, highlighting the robustness of the classification, in some cases pronounced interannual variations are observed for specific wind clusters. For example, at the most coastal station, an increase in PM10 concentration observed in recent years is considerably higher with NNW winds, suggesting the impact of a new or more intense source coming from that sector. These results portray wind-cluster analysis as a valuable tool to understand sources of interannual variation in air quality.

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