Air Quality Degradation Research Articles

Deciphering wintertime air pollution upon the West Lake of Hangzhou, China

The West Lake of Hangzhou, a world famous landscape and cultural symbol of China, suffered from severe air quality degradation in January 2015. In this work, Random Forest (RF) and Recurrent Neural Networks (RNN) are used to analyze and predict air pollutants on the central island of the West Lake. We quantitatively demonstrate that the PM2.5 and PM10 were chiefly associated by the ups and downs of the gaseous air pollutants (SO2, NO2 and CO). Compared with the gaseous air pollutants, meteorological circumstances and regional transport played trivial roles in shaping PM. The predominant meteorological factor for SO2, NO2 and surface O3 was dew-point deficit. The proportion of sulfate in PM10 was higher than that in PM2.5. CO was strongly positively linked with PM. We discover that machine learning can accurately predict daily average wintertime SO2, NO2, PM2.5 and PM10, casting new light on the forecast and early warning of the high episodes of air pollutants in the future.

Clinical Manifestations and Changes of Haematological Markers among Active People Living in Polluted City: The Case of Douala, Cameroon.

Urban air pollution, despite its dangerous health impact, is poorly studied in sub-Saharan Africa (sSA). Epidemiological data on this silent killer are almost non-existent for cities of Cameroon, which seems to be one of the sSA countries where populations are highly exposed to air pollutants. Objective: The present study was conducted in Douala city, and aimed at determining the association of urban air quality degradation with respiratory and systemic health in active populations exposed to air pollutants on a daily basis. Methods: A cross-sectional study was conducted from 2017 to 2019 in 1182 active people consisting of motorbikes drivers (MD), outdoor urban workers (UW), and fuel station sellers (FSS). A standardized questionnaire was used to document participants’ data. One hundred and twenty-six (126) motorbike drivers were selected to evaluate the relationship between haematological (white blood cells, platelets) and inflammatory (C-reactive protein—CRP) biomarkers, and air pollution; compared with those of a sixty-five (65) motorbike drivers’ control group enrolled in Dschang, another town situated at about 216.3 km from Douala. Results: Among those recruited in urban Douala, some respiratory disorders such as running nostrils, colds, common fever, sore throats, dry cough, wheezing, chest pain, shortness of breath and systemic symptoms such as headaches, eye irritation, conjunctivitis, watery eyes and general tiredness were very common among MD, UW, and FSS. Regarding biological data, blood monocytes, lymphocytes and CRP were found to be significantly increased among selected MD in Douala, compared to control groups in Dschang. Conversely, a more significant decrease in blood neutrophil level was observed among MD in Douala than control groups in Dschang. These changes of haematological markers were significantly associated with place of residence, site of activity, and daily duration. Conclusion: Our results suggest the risk of suffering from respiratory impairments and systemic symptoms with exposure to urban air pollution among active people working near highways in Douala.

Assessment of Particulate Matter (PM\(_{10}\)) using Chemistry Transport Modeling in Agadir City, Morocco

According to the World Health Organization (WHO), the effects of outdoor and indoor air pollution result in approximately 7 million early deaths each year. In Morocco's case, the economic cost of air quality degradation is about 1.62 percent of GDP. Also, several studies reported the significant influence of local meteorological factors on the PM\(_{10}\) daily concentration during the synoptic climate conditions and cyclonic circulation. In this sense, Agadir city is a coastal city, and its proximity to the desert makes it very exposed to particles. Accordingly, this study allows, on one hand, to evaluate the performance and to understand the limitations of the WRF-CHIMERE modeling system used to simulate the maximum concentrations of PM\(_{10}\) in the city of Agadir, based on observations made in spring and summer 2010. On another hand, in order to better understand the situation, the impact of meteorological variables and anthropogenic emissions on PM\(_{10}\) is being investigated. The preliminary results of air quality modeling pointed out some PM\(_{10}\) dispersion issues in the area of Agadir. In particular, the results highlighted the influence of temperature and wind speed, which were correlated with PM\(_{10}\) concentration. Besides, CHIMERE simulations suggested that anthropogenic emissions control is essential to reduce PM\(_{10}\) by up to 15\%. The PM\(_{10}\) underestimation is attributed to the meteorological observation/model discrepancy and the effect of emissions. The results underline the importance of meteorology on PM\(_{10}\) dispersion and have significant policy considerations for Moroccan air quality strategy.

The impact of tourism on the conservation and IAQ of cultural heritage: The case of the Monastery of Jerónimos (Portugal)

Cultural heritage plays a crucial role in modern societies as a symbol of their past and as a way to safeguard their identity in a continuously changing world. Interest in cultural tourism has been growing significantly, and in 2015 it was estimated that it was responsible for 40% of European tourism.Cultural tourism can be a major contribution to the economy of each country, as well as a potential vehicle in facilitating the preservation of cultural heritage if properly managed. However, the high number of visitors will contribute to higher humidity and CO2, disrupting the historic climate, and can constitute a real risk for the conservation and indoor air quality. COVID-19 has slowed tourist routes around the world, and this reflection period can be used to assess the sustainability of mass tourism.This paper intends to evaluate the impact of tourism on one of the most emblematic Portuguese monuments, the Monastery of Jerónimos, a UNESCO World Heritage building located in Lisbon. For this purpose, a simulation model of the Monastery was developed with the software WUFI®Plus and validated against the real data. The impact of visitors was evaluated according to the past occupancy, and a forecast for 2027 was performed, analysing the risks for conservation and indoor air quality. It was possible to conclude that even for the current data there was already a risk of fungi proliferation, and that any of the future considered scenarios increases this risk and contributes to the degradation of the indoor air quality.

Atmospheric Concentrations and Health Implications of PAHs, PCBs and PCDD/Fs in the Vicinity of a Heavily Industrialized Site in Greece

Background: Thriassion Plain is considered the most industrialized area in Greece and thus a place where emissions of pollutants are expected to be elevated, leading to the degradation of air quality. Methods: Simultaneous determination of polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) was performed in PM10 samples. SPSS statistical package was employed for statistical analysis and source apportionment purposes. Cancer risk was estimated from total persistent organic pollutants’ (POPs) dataset according to the available literature. Results: POPs concentrations in particulate matter were measured in similar levels compared to other studies in Greece and worldwide, with mean concentrations of ΣPAHs, ΣPCDD/Fs, dioxin like PCBs, and indicator PCBs being 7.07 ng m−3, 479 fg m−3, 1634 fg m−3, and 18.1 pg m−3, respectively. Seasonal variations were observed only for PAHS with higher concentrations during cold period. MDRs, D/F ratios, and principal component analysis (PCA) highlighted combustions as the main source of POPs’ emissions. Estimation of particles’ carcinogenic and mutagenic potential indicates the increased toxicity of PM10 during cold periods, and cancer risk assessment concludes that 3 to 4 people out of 100,000 may suffer from cancer due to POPs’ inhalation. Conclusions: Increased cancer risk for citizens leads to the necessity of chronic POPs’ monitoring in Thriassion Plain, and such strategies have to be a priority for Greek environmental authorities.

An assessment of emission characteristics of Northern Hemisphere cities using spaceborne observations of CO2, CO, and NO2

Intensified anthropogenic activities and high levels of energy consumption in cities have led to an increase in emissions of CO2 and air pollutants, impacting air quality and calling for better measures to monitor and reduce emissions. This study assesses the emission characteristics of cities in the Northern Hemisphere during two winter seasons from December 2018 to March 2020 using a combination of CO2 observations from the Orbiting Carbon Observatory-2 (OCO-2) along with CO and NO2 observations from the Sentinel-5 Precursor TROPOspheric Monitoring Instrument (S-5P TROPOMI). We calculate the estimates of urban enhancement concentrations of CO2, CO, and NO2 from anthropogenic emissions in cities. Moreover, using ratios of CO/CO2 and NO2/CO2 according to each city, we analyze the relationship between CO2 and air pollutants and find that cities show distinct emission patterns according to where they are located in different regions of the world. Our analysis shows that a positive relationship exists in the comparisons of CO/CO2 and NO2/CO2 ratios to city population and GDP. However, when cities in the Northern Hemisphere are divided into “developed” and “developing” regions, a difference in pattern is found where most developed cities show a smaller increase of both CO/CO2 and NO2/CO2 ratios with the increase of GDP, while developing cities show a larger increase of ratios per increase of GDP. Especially, developing cities facing rapid economic development like Mumbai and Tianjin show high emission ratios that almost match that of developed cities. The higher incline of increase in emission ratios in developing cities can be attributed to the low combustion efficiency of fossil fuels along with less stringent pollution control measures. This implies that pollution control measures are crucial for effective management of air quality degradation with economic advancement within these developing cities. The analysis also highlights the importance of urban geological features in cities such as that of Tehran and Milan which can trap air pollution under appropriate meteorological conditions. Despite the short period of analysis, our study demonstrates that satellite observations of CO2 and air pollutants together can provide clues about factors controlling the co-emission of air pollutants and carbon in cities and suggests that the application of the proposed methods with longer periods of observation will support coupled air quality and climate mitigation strategies.

Eco-friendly utilization of rice husk ash and bagasse ash blend as partial sand replacement in self-compacting concrete

Self-compacting concrete (SCC) is largely used construction material worldwide, uplifting the demand for river sand along with all of its constituents due to the recent construction boom. Rice husk ash (RHA) and Bagasse ash (BA) are the biomass waste of the abundantly produced crops in Pakistan, which causes several cardiovascular diseases to humans and poses threats to degrade air quality as well.Characterization of both RHA and BA was performed at the macro and microstructural level to study their suitability as fine aggregate in SCC. This research aims to study the effect of environment-friendly substitution of river sand with blended waste ashes of RHA and BA on microstructural, fresh, physicomechanical and sulfate resistant properties of SCC.The results of microstructural characterization revealed the pozzolanic nature of ashes is evident in Chapelle activity test and the adsorptive natured siliceous micro-sized ash particles contribute toward higher water demand in SCC. The scanning electron microscopy (SEM) analysis of SCC mixes containing blended ashes of RHA and BA revealed that the formation of secondary calcium silicate hydrate (CSH) gel occurred at a calcium to silica (Ca/Si) ratio of 1.41 as evident in Energy Dispersive X-ray Spectroscopy (EDX) analysis. The results of rheological properties revealed that the fluidity of SCC mixes reduced due to the porous nature of incorporated ashes, whereas the viscosity of the mixes improved upon the incorporation of blended ashes. The physicomechanical properties include water absorption, hardened density, compressive strength, and split tensile strength. The physicomechanical properties depicted that the 20% collective incorporation of waste ashes produced structural lightweight concrete confirming ACI 213R with the compressive strength and hardened density values of 20 MPa and 1816 Kg/m3, respectively. Conclusively, the eco-friendly utilization of blended ashes of RHA and BA improved the microstructure, viscosity, physicomechanical properties, and sulfate resistance of SCC.

Does Haze Drive Pro-Environmental and Energy Conservation Behaviors? Evidence from the Beijing-Tianjin-Hebei Area in China

Humans conduct themselves in relation to energy use; energy use has degraded air quality, as reflected by haze occurrence in countries such as China. Improving the population’s involvement in environmental and energy conservation necessitates understanding their motivation to behave under haze. Considering the social problems caused by haze conditions in China, this study used people’s risk perception as a basis to determine their motivations to perform pro-environmental and energy-saving behaviors. We analyzed motivation from privately and publicly oriented perspectives as well as adaptive and mitigative behavioral viewpoints. Motivation-related data were collected through face-to-face discussion and a survey of 506 respondents in the Beijing-Tianjin-Hebei area, which is one of the most heavily polluted regions in China. We conducted multiple regression analysis to determine the extent to which socio-demographic characteristics and risk perception concerning haze predict motivation and actual behavior. Results showed that these factors explain 36.8% and 30.5% of privately and publicly oriented motivations, respectively, but more strongly explain more adaptive (i.e., privately oriented; 55.0%) than mitigating (i.e., publicly oriented; 8.8%) behaviors. Although the residents are motivated to behave equally for private and public purposes in initial conservation efforts, they tend to exhibit adaptive behavior more frequently than mitigating behaviors. These results serve as a reference in encouraging China’s residents to act pro-environmentally and use energy conservatively, thereby contributing to environmental and energy saving education for the society.

Combination of data-driven models and interpolation technique to develop of PM10 map for Hanoi, Vietnam

The degradation of air quality is the most concerned issue of our society due to its harmful impacts on human health, especially in cities with rapid urbanization and population growth like Hanoi, the capital of Vietnam. This study aims at developing a new approach that combines data-driven models and interpolation technique to develop the PM10 concentration maps from meteorological factors for the central area of Hanoi. Data-driven models that relate the PM10 concentration with the meteorological factors at the air quality monitoring stations in the study area were developed using the Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) algorithms. Models’ performance comparison showed that ANN models yielded better goodness-of-fit indices than MLR models at all stations in the study area with average coefficient of correlation (r) and Nash–Sutcliffe Efficiency Index (NSE) of 0.51 and 0.34 for the former, and 0.7 and 0.49 for the latter. These indices indicates that the ANN-based data-driven models outperformed the MLR-based models. Thus, the ANN-based models and the Inverse Distance Weighting (IDW) interpolation technique were then combined for mapping the monthly PM10 concentration with a spatial resolution of 1 km from global meteorological data. With this combination, the PM10 concentration maps account for both local PM10 concentration and impacts of spatio-temporal variations of meteorological factors on the PM10 concentration. This study provides a promising method to predict the PM concentration with a high spatio-temporal resolution from meteorological data.

Assessing the Immediate Effect of Covid-19 Lockdown on Air Quality: A Case Study of Delhi, India

Abstract In India, a nationwide lockdown due to COVID-19 has been implemented on 25 March 2020. The lockdown restrictions on more than 1.3 billion people have brought exceptional changes in the air quality all over the country. This study aims to analyze the levels of three major pollutants: particulate matter sized 2.5 μm (PM2.5) and 10 μm (PM10), and nitrogen dioxide (NO2) before and during the lockdown in Delhi, one of the world’s most polluted cities. The data for PM2.5, PM10, and NO2 concentrations are derived from 38 ground stations dispersed within the city. The spatial interpolation maps of pollutants for two times are generated using Inverse Distance Weighting (IDW) model. The results indicate decreasing levels of PM2.5, PM10, and NO2 concentrations in the city by 93%, 83%, and 70% from 25 February 2020 to 21 April 2020 respectively. It is found that one month before the lockdown the levels of air pollution in Delhi were critical and much higher than the guideline values set by the World Health Organization. The levels of air pollution became historically low after the lockdown. Considering the critically degraded air quality for decades and higher morbidity and mortality rate due to unhealthy air in Delhi, the improvement in air quality due to lockdown may result as a boon for the better health of the city’s population.

Atmospheric deposition of arsenic, cadmium, copper, lead, and zinc near an operating and an abandoned lead smelter.

Atmospheric deposition samples were collected over 15 mo at several locations near an operating smelter and an abandoned Pb smelter to investigate the contribution of Pb smelting to depositional fluxes and potential local air quality degradation. Samples were analyzed for As, Cd, Cu, Pb, and Zn and subjected to scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS). Concentrations of Cd and Pb at both sites were greater than at the control site (p<.05), and significant correlations existed between Cd and Pb concentrations at both sites (p<.05). Monthly depositional flux variations at both sites were similar, with greater deposition during cold and dry periods. Heavy metal(loid)s deposition during these periods was correlated with wind speed. Greater Cd depositional flux differences were found between the smelter and control sites compared with other elements. The SEM images suggested that some particles at the operating smelter site were from Pb smelting material. However, most particles at both sites had no characteristics of smelting, suggesting reactions occurred between the smelter-emitted particles and soil components. The EDS results indicated that atmospheric deposition from both sites had lower Pb concentrations than smelting material or ash. The main atmospheric deposition source at the operating and abandoned sites was likely from the resuspension of heavy metal(loid)-enriched soil particles. Greater risk of air pollution from historical Pb smelting facilities exists years after closing down. Reducing soil wind erosional losses may help reduce heavy metal(loid)s dispersion across environments.

Impact of traffic emissions on air quality in Cabo Verde.

Air quality degradation due to road traffic emissions is one of the topics of major interest for the scientific community and urban planners worldwide. Cabo Verde does not have regulations for traffic emission control or air quality guidelines, although the number of road vehicles has grown steadily over the past decade. Moreover, studies focusing on the impact of road transport on air quality in this archipelago are sparse. In this study, we present a first detailed air pollutant inventory of road traffic emissions through a bottom-up methodology, along with snapshots of the state of air quality on the islands of Santiago, São Vicente, and Sal. For the year 2017, emission estimates for the main island (Santiago) are 654 tons of CO, 35 tons of PM10, 562 tons of NOx, and 84 tons of NMVOCs. The air quality assessment was carried out using the TAPM model for a period of 6months from January to July 2017. The results showed that the mean concentration values for Sao Vicente, Sal, and Santiago Islands ranged between 2.0 and 18μgm-3 for NO2 and 3.8 and 5.6μgm-3 for PM10. NO2 concentrations show an increasing trend from January to July in Santiago and Sal, and no clear trend in São Vicente Island. The simulated PM10 concentrations showed values in the same range over the year, even though they appeared slightly higher in July than in January. It was observed that both NO2 and PM10 average concentrations have been consistently above healthful levels, according to air quality guidelines fixed by the WHO.

Effectiveness of vehicle-free zone in reducing air pollution

This study focuses on the effectiveness of vehicle-free zone in terms of air quality. Particulate matter (PM10, PM2.5) and carbon monoxide (CO) were measured at V1, a core area of vehicle-free zone for three seasons (post-monsoon, winter, and pre-monsoon), seven days each for 12-h time period. PM and CO concentrations were higher in the morning hours, considerably lower during the afternoon and increased during the evening. PM2.5, PM10, and CO were found to be 28.49 ± 15.10 µg/m3, 83.78 ± 46.24 µg/m3, 4.53 ± 3.08 mg/m3 in post-monsoon; 62.49 ± 34.37 µg/m3, 89.28 ± 34.91 µg/m3, and 7.9 ± 4.76 mg/m3 in winter; 27.41 ± 11.16 µg/m3, 42.12 ± 15.35 µg/m3, and 5.27 ± 0.56 mg/m3 in pre-monsoon, respectively. PM was found to be lower in the vehicle-free zone than the reference stations (R1 and R2) as well as before the vehicle-free intervention. However, there were occasional mornings and evenings with higher emissions as compared to the National Ambient Air Quality Standards (NAAQS) and the World Health Organization (WHO) air quality standards guidelines. This means that background pollution and atmospheric conditions might have a greater impact on the degradation of the ambient air quality to which the population is exposed chronically. Despite these results, the decrease in particulate matter concentration also suggests that these regulations could be one of the effective measures to control air pollution.

Simulation of an extreme dust episode using WRF-CHEM based on optimal ensemble approach

Extreme dust episodes have been noticeably increasing in recent years. Dust burden during such events imparts several threats to the environment and human health. Therefore, forecast of such extreme events becomes of utmost importance to minimise the adverse impact on various socio-economy sectors. In the present study model experiments have been carried out for the simulation of an extreme dust episode that emanated over the western Indian region that coupled with previously transported dust from the West Asia region and resulted in the highly degraded air quality over the Indian region. For this purpose four ensemble members, using Weather Research and Forecasting model fully coupled with chemistry (WRF-CHEM), have been generated for identical model configuration but for the perturbed initial conditions. Model performance has been evaluated with respect to the available ground based measurements from Central Pollution Control Board (CPCB) and the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2) data sets using standard statistical measures. Ensemble spread is noted amongst the four ensemble members generated based on 4 varying initial conditions, therefore it is suggested to use ensemble mean forecast for the dust storm monitoring and analysis. It is revealed from the analysis based on the categorical validation scheme that the WRF-CHEM simulated dust load is able to capture the locational accuracy with respect to the reanalysis/observational data sets over Indian subcontinent fairly well with 0% false alarm ratio, 78–92% probability of detection and 79–90% accuracy. It is noted that thick blanket of dust load enveloped Northern part of India subsequent to the dust storm which resulted in substantially dropped ground reaching solar radiation (~100–150 W/m2) and a consequential reduction in the surface temperature (~2 °C). Further to this enhanced temperature in association with reduced relative humidity from 800 to 600 hPa has also been noted in response to the enhanced dust loading in the model simulations. Results obtained in the present study suggests that WRF-CHEM is able to simulate both the direct and semi-direct effects of dust aerosols reasonably well. Present work has implications for improved prediction skills of WRF-CHEM in simulating extreme dust episodes and investigating the impact of dust aerosols on weather and climate.

Post-monsoon air quality degradation across Northern India: assessing the impact of policy-related shifts in timing and amount of crop residue burnt

The past decade has seen episodes of increasingly severe air pollution across much of the highly populated Indo-Gangetic Plain (IGP), particularly during the post-monsoon season when crop residue burning (CRB) is most prevalent. Recent studies have suggested that a major, possibly dominant contributor to this air quality decline is that northwest (NW) Indian rice residue burning has shifted later into the post-monsoon season, as an unintended consequence of a 2009 groundwater preservation policy that delayed the sowing of irrigated rice paddy. Here we combine air quality modelling of fine particulate matter (PM2.5) over IGP cities, with meteorology, fire and smoke emissions data to directly test this hypothesis. Our analysis of satellite-derived agricultural fires shows that an approximate 10 d shift in the timing of NW India post-monsoon residue burning occurred since the introduction of the 2009 groundwater preservation policy. For the air quality crisis of 2016, we found that NW Indian CRB timing shifts made a small contribution to worsening air quality (3% over Delhi) during the post-monsoon season. However, if the same agricultural fires were further delayed, air quality in the CRB source region (i.e. Ludhiana) and for Delhi could have deteriorated by 30% and 4.4%, respectively. Simulations for other years highlight strong inter-annual variabilities in the impact of these timing shifts, with the magnitude and even direction of PM2.5 concentration changes strongly dependent on specific meteorological conditions. Overall we find post-monsoon IGP air quality to be far more sensitive to meteorology and the amount of residue burned in the fields of NW India than to the timing shifts in residue burning. Our study calls for immediate actions to provide farmers affordable and sustainable alternatives to residue burning to hasten its effective prohibition, which is paramount to reducing the intensity of post-monsoon IGP air pollution episodes.

Regional sensitivities of air quality and human health impacts to aviation emissions

Emissions from civil aviation degrade air quality, and have been estimated to lead to ∼16 000 premature deaths annually. Previous studies have indicated that aviation emissions in different regions have varying corresponding air quality and human health impacts. Given the global nature of aviation activity and its forecasted regionally heterogeneous growth, this phenomenon poses challenges in aviation air quality decision making. In this study, we quantify the differences in the regional air quality responses to aviation emissions, and analyze their drivers. Specifically, we use the GEOS-Chem atmospheric chemistry-transport model to quantify the regional fine particulate matter (PM2.5) and ozone sensitivity to aviation emissions over Asia, Europe, and North America for 2005. Simulations with perturbed regional aviation emissions are used to isolate health impacts of increases in aviation emissions originating from and occurring in different regions. Health impacts are evaluated as premature mortality attributed to both landing and takeoff and cruise emissions. We find that the sensitivity of PM2.5 global population exposure to full-flight emissions over Europe is 57% and 65% higher than those to emissions over Asia and North America, respectively. Additionally, the sensitivity of ozone global population exposure to aviation emissions over Europe is larger than to emissions over Asia (32%) and North America (36%). As a result, a unit of fuel burn mass over Europe results in 45% and 50% higher global health impacts than a unit of fuel burn mass over Asia and North America, respectively. Overall, we find that 73% and 88% of health impacts from aviation emissions over Europe and North America, respectively, occur outside the region of emission. These results suggest that inter-regional effects and differences in regional response to emissions should be taken into account when considering policies to mitigate air quality impacts from aviation, given the projected spatially heterogeneous growth in air transportation.

On deriving influences of upwind agricultural and anthropogenic emissions on greenhouse gas concentrations and air quality over Delhi in India: A stochastic Lagrangian footprint approach

Delhi, the capital city of India witnesses severe degradation of air quality and rapid enhancement of trace gases during winter. Still it is unclear about the relative role of the meteorological conditions and the post-monsoon agricultural stubble burning on the occurrence of these events. To overcome this, we examine the use of applying high-resolution transport model to establish the link between atmospheric concentrations and upstream surface fluxes. This study reports the implementation of a Lagrangian approach and demonstrates its capability in deriving the upwind influences over Delhi. We simulate stochastic back trajectories over Delhi by implementing stochastic time-inverted Lagrangian transport (STILT) model, driven by the meteorological fields from the European Centre for Medium Range Weather Forecasts (ECMWF) model. During the post-monsoon, when mixing layer height is shallow, we find high near-field influence. The variations in footprint simulations with receptor heights show the effect of mixing layer dynamics on the air-parcels. By using atemporal emission fields, we find a considerable impact of meteorological conditions during November that contributes to the enhancements of trace gases. Together with strong emissions (anthropogenic and biomass burning), these enhancements can be several orders higher compared to other seasons. Through the receptor-oriented STILT implementation over India, we envision a wide range of applications spanning from air quality to climate change. An advantage of this implementation is that it allows the use of pre-calculated footprints in simulating any trace gas species and particulate matter, making it computationally less demanding than running an ensemble of full atmospheric transport model.

Poluição atmosférica em cidades brasileiras: uma breve revisão dos impactos na saúde pública e meio ambiente

Estima-se que atualmente cerca de 50% da população mundial habita em cidades e aglomerados urbanos podendo estar sujeitas a níveis crescentes de poluentes do ar. Dentre as matérias consideradas poluentes atmosféricos, destacam-se os gases e material particulado proveniente, sobretudo de fontes antrópicas, como os veículos automotores e as indústrias. Estima-se que no Brasil a degradação da qualidade do ar atmosférico possa causar aproximadamente 20 mil óbitos/ano, valor cinco vezes maior ao de morte causado pelo tabagismo ambiental/passivo, e 10,7 mil mortes/ano resultante da poluição do ar em ambientes internos. Nesse sentido, a pesquisa tem por objetivo desenvolver um levantamento bibliográfico a respeito dos principais impactos provenientes da poluição atmosférica na saúde pública e no meio ambiente, dando preferência a trabalhos publicados a partir do ano de 2008. A pesquisa se classifica como exploratória, abordando a problemática de forma flexível e considerando vários aspectos do fato estudado. Os estudos apresentados demonstram que os grandes centros urbanos são os mais suscetíveis a poluição do ar e que no geral, as populações mais vulneráveis são as de menor poder aquisitivo e as faixas etárias mais acometidas por agravos na saúde são crianças e idosos, nesse sentido, o monitoramento através de indicadores da saúde e bioindicadores são instrumentos válidos na observação dos impactos relacionados a poluição do ar.

Evaluating an Air Quality Health Index (AQHI) amendment for communities impacted by residential woodsmoke in British Columbia, Canada

ABSTRACT Smoke from burning biomass is an important source of fine particulate matter (PM2.5), but the health risks may not be fully captured by the Canadian Air Quality Health Index (AQHI). In May 2018, the province of British Columbia launched an evidence-based amendment (AQHI-Plus) to improve AQHI performance for wildfire smoke, but the AQHI-Plus was not developed or tested on data from the residential woodsmoke season. This study assesses how the AQHI and AQHI-Plus are associated with acute health outcomes during the cooler seasons of 2010–2017 in British Columbia, Canada. Monthly and daily patterns of temperature and PM2.5 concentrations were used to identify Local Health Areas (LHAs) that were impacted by residential woodsmoke. The effects of the AQHI and AQHI-Plus on five acute health outcomes (including non-accidental mortality, outpatient physician visits, and medical dispensations for cardiopulmonary conditions) were estimated using generalized linear mixed effect models with Poisson distributions adjusted for long- and short-term temperature trends. Values of the Akaike information criterion (AIC) were compared to evaluate whether the AQHI or AQHI-Plus was better fitted to each health outcome. Eleven LHAs were categorized as woodsmoke-impacted. In these LHAs, the AQHI and AQHI-Plus associations with acute health outcomes were sensitive to temperature adjustments. After temperature adjustments, the most consistent associations were observed for the two asthma-specific outcomes where the AQHI-Plus was better fitted than the AQHI. The improved performance of the AQHI-Plus for susceptible populations with asthma is consistent between communities impacted by residential woodsmoke and wildfire smoke. Implications: Canada’s Air Quality Health Index (AQHI) is a three pollutant index used to communicate the short term health impact of degraded air quality. As fine particulate matter (PM2.5) is the lowest weighted pollutant in the AQHI, the index is poorly reflective of woodsmoke impacts. The present analysis found that an AQHI amendment developed for improved sensitivity to PM2.5 during wildfire seasons (AQHI-Plus) is also more predictive of acute asthma-related health outcomes in communities impacted by residential woodsmoke. The BC Ministry of Environment and Climate Change Strategy has piloted the AQHI-Plus year-round. Other jurisdictions should consider whether their air quality indices are reflective of the risks posed by woodsmoke.

Long-term increase in atmospheric stagnant conditions over northeast Asia and the role of greenhouse gases-driven warming

Abstract The recent trend in the air quality degradation of urban South Korea prompted the authors to examine the long-term changes in the near-surface wind speed and its link with the lower atmospheric circulation, using modern reanalysis datasets. Analyses based on JRA-55 data show a negative correlation between near-surface wind speed and static stability over the Yellow Sea and the western part of South Korea. Near-surface wind speed shows a clear declining trend accompanied by increased static stability, while its negative correlation strengthened recently. Further investigations using CMIP5 single-forcing experiments suggest that global warming because of anthropogenic greenhouse gases probably increased static stability in the lower troposphere, implying further atmospheric stagnant conditions in the future.