Elevated Air Pollution Concentrations Research Articles

Does air pollution impact myocardial infarction incidence even in a city with fair air quality? Results from the EPIC-MI (Environmental Pollution and IncidenCe of Myocardial Infarction) Study

Abstract Background In light of recent research highlighting the potential association between air pollution and cardiovascular diseases, there remains a gap in data, particularly in cities characterized by relatively low pollution levels. The EPIC-MI Study endeavors to explore whether, even in a city boasting fair air quality such as our city, there exists a discernible impact of air pollution on the risk of cardiovascular events within an urban setting. Methods We analyzed all consecutive acute myocardial infarction (MI) patients admitted to our city heart center from March 2013 to December 2022. Air pollution data were meticulously gathered from 5 strategically positioned monitoring stations. Utilizing Poisson regression, the associations between these pollutants and the incidence of MI was analyzed. We also investigated the impact of pollution exceedance days and COVID-19 lockdown periods on MI incidence. Results Over nearly a decade, 18.798 MI cases were analyzed. The Poisson regression model revealed a significant independent association between the monthly average MI incidence and pollutant concentrations within the same month. Statistically significant independent effects were observed for CO (p<0.01), O₃ (p=0.03), SO₂ (p<0.01), and relative humidity (p<0.01) on MI incidence (Figure 1). Exceedance days were associated with a significant upswing in daily MI incidence. The MI incidence increased by 3.3% when PM10 exceeded 25 µg/m³ on the same day (5.19 ± 2.49 vs. 5.36 ± 2.50, p=0.03) and remained elevated over three days (5.19 ± 1.42 vs. 5.34 ± 1.46, p<0.01). For PM2.5, there was a 4.2% increase when exceeding 20 µg/m³ on the same day (5.20 ± 2.49 vs. 5.42 ± 2.52, p=0.02) and still elevated over three days (5.20 ± 1.42 vs. 5.40 ± 1.47, p<0.01). During the COVID-19 lockdown periods, a significant decrease was observed in air pollutant levels compared to non-lockdown years within the same timeframe (Figure 2). PM2.5 (9.89 µg/m³ vs. 12.76 µg/m³, p=0.02), PM10 (15.26 µg/m³ vs. 18.7 µg/m³, p<0.01), SO2 (1.16 µg/m³ vs. 1.77 µg/m³, p<0.01), and NO2 (14.42 µg/m³ vs. 19.53 µg/m³, p<0.01) exhibited significant reductions. Concurrently, a 22.5% reduction in daily MI incidence was observed compared to non-lockdown years within the same timeframe (4.16 vs. 5.37, p<0.01). Conclusion The study demonstrates an enduring influence of air pollutants on cardiovascular events, even in a city with fair air quality, such as our city. Elevated concentrations of air pollutants, especially on days with excessive levels, were significantly associated with an increased incidence of MI. The reduction in MI cases observed during the COVID-19 lockdown period underscores the potential cardiovascular benefits associated with improved air quality. These findings emphasize the importance of sustained efforts to mitigate air pollution for the enhancement of cardiovascular health in urban environments.

Air pollution and cancer daily mortality in Hangzhou, China: an ecological research

BackgroundLong-term exposure to air pollution has been linked to cancer incidence. However, the evidence is limited regarding the effect of short-term exposure to air pollution on cancer mortality.ObjectivesThis study aimed...

Exploring the adverse effect of fine particulate matter (PM2.5) on wildland firefighters’ pulmonary function and DNA damage

Chiang Mai encounters severe pollution during the wildfire season. Wildland firefighters encounter various hazards while engaged in fire suppression operations, which encompass significant exposure to elevated concentrations of air pollutants resulting from combustion, especially particulate matter. The adverse effects of wildfire smoke on respiratory health are a significant concern. The objective of this study was to examine the potential adverse effects of PM2.5 exposure on the respiratory function and DNA damage of wildland firefighters. This prospective cohort study conducted in Chiang Mai from January to May 2022 planned to evaluate the health status of wildland firefighters during the pre-peak, peak, and post-peak ambient air pollution seasons. The measurement of PM2.5 was done at every forest fire station, as well as utilizing data from the Pollution Control Department. Participants received general health examinations, spirometry evaluations, and blood tests for DNA damage analysis. Pair t-tests and multiple regression models were used to examine the connection between pulmonary function parameters (FVC, FEV1) and PM2.5 concentration, with a significance level of P < 0.05. Thirty-three peak-season and twenty-one post-peak-season participants were enrolled. Four pre-peak-season wildland firefighters had FVC and FEV1 declines of > 15%. Multiple regression analysis showed a negative association between PM2.5 exposure and FVC% predicted (− 2.81%, 95% CI − 5.27 to − 0.34%, P = 0.027) and a marginally significant negative correlation with FVC (− 114.38 ml, 95% CI − 230.36 to 1.59 ml, P = 0.053). The remaining pulmonary measures showed a statistically insignificant decline. There were no significant changes in DNA damage detected. Wildland firefighters suffered a significant decline in pulmonary function associated with PM2.5 exposure. Spirometry is crucial for monitoring and promptly identifying respiratory issues that occur during wildfire seasons. Further research is recommended to explore DNA damage alterations and their potential association with PM2.5.

Modification of heat-related effects on mortality by air pollution concentration, at small-area level, in the Attica prefecture, Greece

BackgroundThe independent effects of short-term exposure to increased air temperature and air pollution on mortality are well-documented. There is some evidence indicating that elevated concentrations of air pollutants may lead to increased heat-related mortality, but this evidence is not consistent. Most of these effects have been documented through time-series studies using city-wide data, rather than at a finer spatial level. In our study, we examined the possible modification of the heat effects on total and cause-specific mortality by air pollution at municipality level in the Attica region, Greece, during the warm period of the years 2000 to 2016.MethodsA municipality-specific over-dispersed Poisson regression model during the warm season (May–September) was used to investigate the heat effects on mortality and their modification by air pollution. We used the two-day average of the daily mean temperature and daily mean PM10, NO2 and 8 hour-max ozone (O3), derived from models, in each municipality as exposures. A bivariate tensor smoother was applied for temperature and each pollutant alternatively, by municipality. Α random-effects meta-analysis was used to obtain pooled estimates of the heat effects at different pollution levels. Heterogeneity of the between-levels differences of the heat effects was evaluated with a Q-test.ResultsA rise in mean temperature from the 75th to the 99th percentile of the municipality-specific temperature distribution resulted in an increase in total mortality of 12.4% (95% Confidence Interval (CI):7.76–17.24) on low PM10 days, and 21.25% (95% CI: 17.83–24.76) on high PM10 days. The increase on mortality was 10.09% (95% CI: − 5.62- 28.41) on low ozone days, and 14.95% (95% CI: 10.79–19.27) on high ozone days. For cause-specific mortality an increasing trend of the heat effects with increasing PM10 and ozone levels was also observed. An inconsistent pattern was observed for the modification of the heat effects by NO2, with higher heat effects estimated in the lower level of the pollutant.ConclusionsOur results support the evidence of elevated heat effects on mortality at higher levels of PM10 and 8 h max O3. Under climate change, any policy targeted at lowering air pollution levels will yield significant public health benefits.

Fine particulate matter and daily hospitalizations for mental and behavioral disorders: A time-series study in Ho Chi Minh City, Vietnam

Various adverse health outcomes caused by particulate matter (PM) exposure has been documented, while the evidence for the adverse effects of PM exposure on mental and behavioral disorders (MBDs) is limited. To date, few epidemiological studies, especially in developing countries, have focused on these adverse effects. In the past decade, air pollution sources in Vietnam have noticeably increased, resulting to the elevated concentrations of ambient air pollutants particularly fine PM or PM with an aerodynamic diameter ≤2.5 μm (PM2.5). Hence, investigating the short-term association between PM2.5 and MBDs is worthwhile. In this study, a quasi-Poisson time-series regression analysis was used to investigate the association between PM2.5 exposure and daily hospitalizations for MBDs to the Ho Chi Minh City Mental Health Hospital during 2017–2020. A natural cubic spline smooth function for time was used to screen out long-term and seasonality trends. Stratified analyses were also performed by sex, age, and season. During study period, 9,986 hospitalizations for MBDs were recorded and included in the analysis. Results suggested that a 10 μg/m3 daily increase in PM2.5 concentration was associated with a statistically significant 2.96% (95% confidence interval: 0.23%–5.76%) increase in hospitalizations for MBDs. The effects of PM2.5 exposure on hospital admissions were more pronounced in female patients and the middle-age group (35–59 years). This finding could increase awareness regarding prevention and minimization of MBDs on the public.

Health risks and perceptions of residents exposed to multiple sources of air pollutions: A cross-sectional study on landfill and stone mining in Danang city, Vietnam

Health risks and perceptions of residents living nearby landfills or stone mines/quarries have been well documented; however, the multiple impacts of these two pollution sources have yet to be investigated. This study aims at giving insights into the impacts of residents exposed to two pollution sources in Danang city, Vietnam: Khanh Son landfill and Phuoc Tuong quarry. In this cross-sectional study, 7-point-Likert scale questionnaires were used to collect information from 314 respondents which were divided into three groups: i) Landfill-Stone mine (LS) exposed group within 1 km from both sources, ii) Stone mine (ST) exposed group within 1 km from the stone mine, and iii) the far-exposed group about 2–3 km from the two emission sites. Air pollutants (including H2S, CH4, and total suspended particles (TSP)) and noise levels were also sampled. In addition, we estimated the potential health risk assessment due to the exposure to hydrogen sulphide in the study areas.The findings have shown that 1) There is a statistical difference (p-value < 0.001) between the two exposed groups and far-exposed group regarding health risks and residents’ perceptions; 2) Compared to the ST exposed group, the LS exposed group statistically showed a higher perception to bad odours and skin diseases; lower satisfaction with regards to the personal health condition and the operation of the landfill; and higher willingness to change current living locations; and 3) There is evidence to indicate that elevated concentrations of air pollutants are associated with the high self-reported health risks and residents' perceptions. Urgent actions should be focused on the LS exposed group, landfill and quarry operations to prevent further adverse health effects.

Association between blood pressure and short-term exposure to ambient air pollutants in Beijing, China

Substantial evidences have pointed to a link between hypertension and air pollution. This explored the link between blood pressure and short-term exposure to ambient atmospheric pollutants in a heavily polluted city. A monitoring program was designed to continuously record physical examination data of 1796 participants in Beijing, China from 2013 to 2018, and the individual-level exposure of atmospheric pollutants (PM2.5, PM10, NO2, CO, O3, and SO2) was estimated using land use regression model. A generalized additive mixed-effects model was applied within the investigation of the acute impacts of air pollutants on blood pressure, including systolic blood pressure, diastolic blood pressure, pulse pressure, and mean arterial pressure. Air pollutant concentrations were found to be positively correlated with blood pressure levels after their adjustment for a number of demographic and meteorological elements, e.g. each 10 μg/m3 increment of NO2 resulted in an increment in systolic blood pressure of 0.351 mm Hg (95th percentile confidence interval: 0.001, 0.701; p < 0.05). In addition, stronger associations were found among males and patients with hypertension, and the blood pressure level of outdoor workers was more susceptible to the changes in NO2 concentration. Generally, elevated concentrations of air pollutants contributed to increased levels of blood pressure.

Influence of transboundary air pollution and meteorology on air quality in three major cities of Anhui Province, China

The variations of criteria air pollutants (CAPs), the influence of transboundary air pollution, and the meteorological effects on air quality in Hefei, Fuyang, and Suzhou were investigated during 2015–2019. In Hefei, continuous decreases in the concentrations of PM2.5 (5.5 μg/m3 yr−1) and PM10 (6.7 μg/m3 yr−1) were observed over time. PM2.5 and PM10 concentrations also exhibited substantial downward trends in Fuyang (PM2.5: 9.4 μg/m3 yr−1; PM10: 13.5 μg/m3 yr−1) and Suzhou (PM2.5: 10.9 μg/m3 yr−1; PM10: 9.1 μg/m3 yr−1) during 2017–2019. However, they increased during 2015–2017. NO2 decreased in Suzhou (9.3 μg/m3 yr−1) and Hefei (5.2 μg/m3 yr−1) during 2017–2019, and in Fuyang (5.2 μg/m3 yr−1) over 2016–2018. Alternatively, O3 increased by 8.3, 8.2, and 5.2 μg/m3 yr−1 in Fuyang, Suzhou, and Hefei, respectively. Despite the reductions, PM2.5 and PM10 still substantially exceeded the annual Grade I and Grade II CAAQS. The relationships between the pollutants and meteorological variables were relatively similar with the correlations varying by season. High primary pollutants concentrations were attributed to poorer dispersion, while elevated temperatures and greater solar radiation were related to higher O3 concentrations. The results of 120-h backward trajectories showed that the study areas were dominantly influenced by the northwesterly and northerly winds. Thus, elevated concentrations of most air pollutants observed in the study areas were associated with transboundary regional transport of air pollution from neighboring cities and provinces. This study shows that effective emissions control strategies that would simultaneously reduce PM2.5 and O3 across the cities in Anhui Province and the surrounding provinces are urgently needed.

Effects of chronic exposure to ambient air pollutants, demographic, and socioeconomic factors on COVID-19 morbidity: The Israeli case study

BackgroundRecent studies conducted in several OECD countries have shown that chronic exposure to elevated levels of air pollutants (especially PM2.5, PM10 and NOx), might negatively impact COVID-19 morbidity and mortality rates. The aim of this study was to examine the association between chronic exposure to air pollution in Israeli cities and towns, their demographic and socioeconomic status, and COVID-19 morbidity, during the three local morbidity waves. MethodsWe examined the associations between: (a) annual average concentrations of NOx, CO, PM10, PM2.5 and SO2 in 2016–2019, and demographic and socioeconomic parameters, and (b) COVID-19 positive cases in 279 Israeli cities and towns, in the four state-wide morbidity peaks: 1st wave peak: March 31st, 2020; 2nd wave peaks: July 24th and September 27th, 2020, and the 3rd wave peak: January 17th, 2021, which occurred after the beginning of the nationwide vaccination campaign. These associations were calculated using both Spearman correlations and multivariate linear regressions. ResultsWe found statistically significant positive correlations between the concentrations of most pollutants in 2016–19 and COVID-19 morbidity rate at the first three timepoints but not the 4th (January 17th, 2021). Population density and city/town total population were also positively associated with the COVID-19 morbidity rates at these three timepoints, but not the 4th, in which socioeconomic parameters were more dominant - we found a statistically significant negative correlation between socioeconomic cluster and COVID-19 morbidity. In addition, all multivariate models including PM2.5 concentrations were statistically significant, and PM2.5 concentrations were positively associated with the COVID-19 morbidity rates in all models. ConclusionsWe found a nationwide association between population chronic exposure to five main air pollutants in Israeli cities and towns, and COVID-19 morbidity rates during two of the three morbidity waves experienced in Israel. The widespread morbidity that was related to socioeconomic factors during the 3rd wave, emphasizes the need for special attention to morbidity prevention in socioeconomically vulnerable populations and especially in large household communities. Nevertheless, this ecological study has several limitations, such as the inability to draw conclusions about causality or mechanisms of action. The growing body of evidence, regarding association between exacerbated COVID-19 morbidity and mortality rates and long-term chronic exposure to elevated concentrations of air pollutants should serve as a wake-up call to policy makers regarding the urgent need to reduce air pollution and its harmful effects.

Dispersion Modeling of Air Pollutants in a Hilly City in India

Abstract Vehicular pollution is one of the major sources of air pollution in urban locales that have reportedly elevated concentrations of air pollutants. This study aims to examine the performance...

The botanical biofiltration of elevated air pollution concentrations associated the Black Summer wildfire natural disaster

The ‘Black Summer’ wildfires that affected Australia over the 2019–2020 summer have led to concern over the health effects of exposure to wildfire emissions, and generated a need for means to reduce exposure. Recently, active green infrastructure has been implemented in cities to assist in the removal of urban air pollution, however the filtration of wildfire emissions has not been previously tested. Here, we field trial botanical biofiltration for the reduction of elevated air pollutant concentrations associated with Black Summer. Two active green walls were installed in outdoor environments in Sydney over Black Summer, with the concentrations of NO2, O3 and PM2.5 in ambient and filtered air streams monitored over 14 days with elevated air pollution concentrations due to wildfire emissions. Average pollutant single pass removal efficiencies of 63.17%, 38.79% and 24.84% for NO2, O3 and PM2.5 respectively were recorded, with clean air delivery rates of 558.90 m3/h, 343.19 m3/h and 219.77 m3/h for NO2, O3 and PM2.5 respectively for each 5 m2 biofilter wall. Weak negative associations were observed between the removal efficiency of NO2 and PM2.5 and their corresponding ambient concentrations. Strategic employment of botanical biofiltration may thus be of value in reducing wildfire emissions in sensitive populations.

Identifying air pollution source impacts in urban communities using mobile monitoring.

With increasing population, rapid urbanization, and increased migration to cities, the local impacts of increasing transportation and industrial-related air pollution are of growing concern worldwide. Elevated air pollution concentrations near these types of sources have been linked to adverse health effects including acute and chronic respiratory and cardiovascular diseases. Mobile monitoring has proven to be a useful technique to characterize spatial variability of air pollution in urban areas and pollution concentration gradients from specific sources. A study was conducted in the Kansas City, Kansas (USA) metropolitan area using mobile monitoring to characterize the spatial variability and gradients of air pollutants to identify the contribution of multiple sources on community-level air quality in a complex urban environment. Measurements focused on nitrogen dioxide (NO2), black carbon (BC), and ultrafine particulate matter (UFP). Mobile monitoring showed that median concentrations of these pollutants ranged by up to a factor of three between the communities, with individual measurements ranging over an order of magnitude within the community. Evaluating these air quality measurements with wind direction data highlighted the influence of specific and combinations of air pollution sources on these elevated concentrations, which can provide valuable information to environmental and public health officials in prioritizing and implementing cost-effect air quality management strategies to reduce exposures for urban populations.

Traffic contribution to PM2.5 increment in the near-road environment

A growing number of studies have reported the adverse health effects of long-term exposure to air pollutants, especially fine particulate matter (PM2.5). Vehicular emission sources have been shown to contribute to elevated air pollution concentrations in the near-road environment, including PM2.5, based on monitoring data collected mainly during short-term campaigns. The United States Environmental Protection Agency (EPA) added near-road monitors to its national network to collect long-term National Ambient Air Quality Standard (NAAQS)–comparable data in the near-road environment. The EPA also mandated inclusion of near-road monitoring data in the Air Quality Index to reflect the elevated level of near-road PM2.5 concentrations to which millions of people in major urban areas are exposed to on a daily basis. For the first time, PM2.5 data collected at one of these near-road monitors were compared with those of other NAAQS monitors during 2016 in Houston, Texas. One of these NAAQS monitors was selected based on EPA guidance for quantitative hotspot analyses of particulate matter to represent background concentrations. The near-road PM2.5 increment was statistically significant. The traffic contribution to 24-h PM2.5 increment in the near-road environment was estimated to be about 23% of background concentration, which is close to estimates given by previous studies (22%) and is greater than a recent estimate based on a national-scale data analysis (17%), emphasizing the importance of background monitor selection criteria. Wind speed and direction were shown to have a considerable effect on PM2.5 increment in the near-road environment. A multiple linear regression model was developed to predict 24-h near-road PM2.5 concentrations using background PM2.5 concentration, wind speed, and wind direction. This model explained 83% of the variability of 24-h PM2.5 concentrations in the near-road environment and showed improvement in near-road concentration predictions when accounting for wind speed and wind direction.

The FireWork v2.0 air quality forecast system with biomass burning emissions from the Canadian Forest Fire Emissions Prediction System v2.03

Abstract. Biomass burning activities can produce large quantities of smoke and result in adverse air quality conditions in regional environments. In Canada, the Environment and Climate Change Canada (ECCC) operational FireWork (v1.0) air quality forecast system incorporates near-real-time biomass burning emissions to forecast smoke plumes from fire events. The system is based on the ECCC operational Regional Air Quality Deterministic Prediction System (RAQDPS) augmented with near-real-time wildfire emissions using inputs from the Canadian Forest Service (CFS) Canadian Wildland Fire Information System (CWFIS). Recent improvements to the representation of fire behaviour and fire emissions have been incorporated into the CFS Canadian Forest Fire Emissions Prediction System (CFFEPS) v2.03. This is a bottom-up system linked to CWFIS in which hourly changes in biomass fuel consumption are parameterized with hourly forecasted meteorology at fire locations. CFFEPS has now also been connected to FireWork. In addition, a plume-rise parameterization based on fire-energy thermodynamics is used to define the smoke injection height and the distribution of emissions within a model vertical column. The new system, FireWork v2.0 (FireWork–CFFEPS), has been evaluated over North America for July–September 2017 and June–August 2018, which are both periods when western Canada experienced historical levels of fire activity with poor air quality conditions in several cities as well as other fires affecting northern Canada and Ontario. Forecast results were evaluated against hourly surface measurements for the three pollutant species used to calculate the Canadian Air Quality Health Index (AQHI), namely PM2.5, O3, and NO2, and benchmarked against the operational FireWork v1.0 system (FireWork-Ops). This comparison shows improved forecast performance and predictive skills for the FireWork–CFFEPS system. Modelled fire-plume injection heights from CFFEPS based on fire-energy thermodynamics show higher plume injection heights and larger variability. The changes in predicted fire emissions and injection height reduced the consistent over-predictions of PM2.5 and O3 seen in FireWork-Ops. On the other hand, there were minimal fire emission contributions to surface NO2, and results from FireWork–CFFEPS do not degrade NO2 forecast skill compared to the RAQDPS. Model performance statistics are slightly better for Canada than for the US, with lower errors and biases. The new system is still unable to capture the hourly variability of the observed values for PM2.5, but it captured the observed hourly variability for O3 concentration adequately. FireWork–CFFEPS also improves upon FireWork-Ops categorical scores for forecasting the occurrence of elevated air pollutant concentrations in terms of false alarm ratio (FAR) and critical success index (CSI).

Association of ambient air pollutants and birth weight in Ningbo, 2015–2017

Previous studies have suggested a change of birth weight linked with elevated ambient air pollutant concentrations during the pregnancy. However, investigations of the influence of higher pollutant levels on birth weight change are limited. The goal of this study is to evaluate whether the air pollution of Ningbo is associated with birth weight, and which trimester could be a window period for maternal exposure to air pollution. A total of 170,008 live births were selected in the Ningbo city of Zhejiang, China, from 2015 to 2017. We estimated the association between the decreased birth weight and the increased air pollutant concentrations in the three trimesters and full gestation. The effects of interaction among pollutants were identified using a co-pollutant adjustment model. An interquartile range increases in PM2.5 (10.55 μg/m3), SO2(4.6 μg/m3), CO (125.59 μg/m3), and O3 (14.54 μg/m3) concentrations during the entire gestation were associated with 3.65 g (95% confidence interval: −6.02 g, −1.29 g), 5.02 g (−6.89 g, −3.14 g), 2.64 g (−4.65 g, −0.63 g) and 2.9 g (−4.8 g, 1 g) decreases, respectively, in birth weight. With each interquartile range increment in NO2 concentration was associated with an 8.05 g (6.24 g, 9.85 g) increase in birth weight. In the first trimester, only the PM2.5 exposure seemed to be associated with the greatest decline in birth weight. After adjustment for co-pollutant, both PM2.5 and SO2 were still associated with birth weight, except for CO for O3 adjustment, O3 for SO2 adjustment, and O3 for NO2 adjustment. Maternal exposure to air pollution may be associated with a decrease of birth weight, but the contribution of various pollutants is necessary to verify by future research.

Black Carbon Reduces the Beneficial Effect of Physical Activity on Lung Function.

When physical activity is promoted in urban outdoor settings (e.g., walking and cycling), individuals are also exposed to air pollution. It has been reported that short-term lung function increases as a response to physical activity, but this beneficial effect is hampered when elevated air pollution concentrations are observed. Our study assessed the long-term impact of air pollution on the pulmonary health benefit of physical activity. Wearable sensors were used to monitor physical activity levels (SenseWear) and exposure to black carbon (microAeth) of 115 healthy adults during 1 wk in three European cities (Antwerp, Barcelona, London). The experiment was repeated in three different seasons to approximate long-term behavior. Spirometry tests were performed at the beginning and end of each measurement week. All results were averaged on a participant level as a proxy for long-term lung function. Mixed effect regression models were used to analyze the long-term impact of physical activity, black carbon and their interaction on lung function parameters, forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC, forced expiratory flow (FEF)25-75, and peak expiratory flow. Interaction plots were used to interpret the significant interaction effects. Negative interaction effects of physical activity and black carbon exposure on FEV1 (P = 0.07), FEV1/FVC (P = 0.03), and FEF25-75 (P = 0.03) were observed. For black carbon concentrations up to approximately 1 μg·m, an additional MET·h·wk resulted in a trend toward lung function increases (FEV1, FEV1/FVC, and FEF25-75 increased 5.6 mL, 0.1% and 14.5 mL·s, respectively). We found that lung function improved with physical activity at low black carbon levels. This beneficial effect decreased in higher air pollution concentrations. Our results suggest a greater need to reduce air pollution exposures during physical activity.

Source contributions to sulfur and nitrogen deposition – an HTAP II multi-model study on hemispheric transport

Abstract. With the rising anthropogenic emissions from human activities, elevated concentrations of air pollutants have been detected in the hemispheric air flows in recent years, aggravating the regional air pollution and deposition issues. However, the regional contributions of hemispheric air flows to deposition have been given little attention in the literature. In this light, we assess the impact of hemispheric transport on sulfur (S) and nitrogen (N) deposition for six world regions: North America (NA), Europe (EU), South Asia (SA), East Asia (EA), Middle East (ME) and Russia (RU) in 2010, by using the multi-model ensemble results from the 2nd phase of the Task Force Hemispheric Transport of Air Pollution (HTAP II) with 20 % emission perturbation experiments. About 27 %–58 %, 26 %–46 % and 12 %–23 % of local S, NOx and NH3 emissions and oxidation products are transported and removed by deposition outside of the source regions annually, with seasonal variation of 5 % more in winter and 5 % less in summer. The 20 % emission reduction in the source regions could affect 1 %–10 % of deposition in foreign continental regions and 1 %–14 % in foreign coastal regions and the open ocean. Significant influences are found from NA to the North Atlantic Ocean (2 %–14 %), and from EA to the North Pacific Ocean (4 %–10 %) and to western NA (4 %–6 %) (20 % emission reduction). The impact on deposition caused by short-distance transport between neighboring regions (i.e., from EU to RU) occurs throughout the whole year (slightly stronger in winter), while the long-range transport (i.e., from EA to NA) mainly takes place in spring and fall, which is consistent with the seasonality found for hemispheric transport of air pollutants. Deposition in the emission-intensive regions such as US, SA and EA is dominated (∼80 %) by own-region emissions, while deposition in the low-emission-intensity regions such as RU is almost equally affected by foreign exported emissions (40 %–60 %) and own-region emissions. We also find that deposition of the coastal regions or the near-coastal open ocean is twice more sensitive to hemispheric transport than the non-coastal continental regions, especially for regions in the downwind direction of emission sources (i.e., west coast of NA). This study highlights the significant impacts of hemispheric transport of air pollution on the deposition in coastal regions, the open ocean and low-emission-intensity regions. Further research is proposed to improve the ecosystem and human health, with regards to the enhanced hemispheric air flows.

Strategies for Development and Improvement of the Urban Fabric: A Vienna Case Study

Numerous studies have shown that densely developed and populated urban areas experience significant anthropogenic heat flux and elevated concentrations of air pollutants and CO2, with consequences for human health, thermal comfort, and well-being. This may also affect the atmospheric composition and circulation patterns within the urban boundary layer, with consequences for local, regional, and global climate. One of the resulting local implications is the increase in urban air temperature. In this context, the present contribution explores urban fabric development and mitigation strategies for two locations in the city of Vienna, Austria. Toward this end, the potential of specific planning and mitigation strategies regarding urban overheating was assessed using a state-of-the-art CFD-based (computational fluid dynamics) numeric simulation environment. The results display different levels of effectiveness for selected design and mitigation measures under a wide range of boundary conditions.

Association of Changes in Air Quality With Bronchitic Symptoms in Children in California, 1993-2012

K Berhane, ML Chang, R McConnell. JAMA. 2017;315(14):1491–1501 Exposure to elevated concentrations of ambient air pollutants is associated with increases in the prevalence of bronchitic symptoms in children. The authors hypothesized that reductions in measured air pollutants over the periods studied would be associated with an improvement in respiratory symptoms in children with or without asthma. Data were collected from 3 successively recruited cohorts involving 4602 children (48% female subjects, age range of 5–18 years, mean age of 8 years, 45% Hispanic) from 8 Southern California communities during the years 1993 to 2001, 1996 to 2004, and 2003 to 2012. This was a longitudinal study with data from the 3 separate …

Atmospheric pollution over the eastern Mediterranean during summer – a review

Abstract. The eastern Mediterranean (EM) is one of the regions in the world where elevated concentrations of primary and secondary gaseous air pollutants have been reported frequently, mainly in summer. This review discusses published studies of the atmospheric dispersion and transport conditions characterizing this region during the summer, followed by a description of some essential studies dealing with the corresponding concentrations of air pollutants such as ozone, carbon monoxide, total reactive nitrogen, methane, and sulfate aerosols observed there. The interlaced relationship between the downward motion of the subsiding air aloft induced by global circulation systems affecting the EM and the depth of the Persian Trough, a low-pressure trough that extends from the Asian monsoon at the surface controlling the spatiotemporal distribution of the mixed boundary layer during summer, is discussed. The strength of the wind flow within the mixed layer and its depth affect much the amount of pollutants transported and determine the potential of the atmosphere to disperse contaminants off their origins in the EM. The reduced mixed layer and the accompanying weak westerlies, characterizing the summer in this region, led to reduced ventilation rates, preventing an effective dilution of the contaminants. Several studies pointing at specific local (e.g., ventilation rates) and regional peculiarities (long-range transport) enhancing the build-up of air pollutant concentrations are presented. Tropospheric ozone (O3) concentrations observed in the summer over the EM are among the highest over the Northern Hemisphere. The three essential processes controlling its formation (i.e., long-range transport of polluted air masses, dynamic subsidence at mid-tropospheric levels, and stratosphere-to-troposphere exchange) are reviewed. Airborne campaigns and satellite-borne initiatives have indicated that the concentration values of reactive nitrogen identified as precursors in the formation of O3 over the EM were found to be 2 to 10 times higher than in the hemispheric background troposphere. Several factors favor sulfate particulate abundance over the EM. Models, aircraft measurements, and satellite-derived data have clearly shown that sulfate has a maximum during spring and summer over the EM. The carbon monoxide (CO) seasonal cycle, as obtained from global background monitoring sites in the EM, is mostly controlled by the tropospheric concentration of the hydroxyl radical (OH) and therefore demonstrates high concentrations over winter months and the lowest concentrations during summer when photochemistry is active. Modeling studies have shown that the diurnal variations in CO concentration during the summer result from long-range CO transport from European anthropogenic sources, contributing 60 to 80 % of the boundary-layer CO over the EM. The values retrieved from satellite data enable us to derive the spatial distribution of methane (CH4), identifying August as the month with the highest levels over the EM. The outcomes of a recent extensive examination of the distribution of methane over the tropospheric Mediterranean Basin, as part of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) program, using model simulations and satellite measurements, are coherent with other previous studies. Moreover, this methane study provides some insight into the role of the Asian monsoon anticyclone in controlling the variability of CH4 pollutant within mid-to-upper tropospheric levels above the EM in summer.