Particulate matter and daily mortality and hospital admissions in the west midlands conurbation of the United Kingdom: associations with fine and coarse particles, black smoke and sulphate

Health risks and sources of trace elements and black carbon in PM2.5 from 2019 to 2021 in Beijing

A comprehensive health risk assessment of PM2.5 is meaningful to understand the current status and directions regarding further improving air quality from the perspective of human health. In this study, we evaluated the health risks of PM2.5 as well as highly toxic inorganic components, including heavy metals (HMs) and black carbon (BC) based on long-term observations in Beijing from 2019 to 2021. Our results showed that the relative risks of chronic obstructive pulmonary disease, lung cancer, acute lower respiratory tract infection, ischemic heart disease, and stroke decreased by 4.07%-9.30% in 2020 and 2.12%-6.70% in 2021 compared with 2019. However, they were still at high levels ranging from 1.26 to 1.77, in particular, stroke showed the highest value in 2021. Mn had the highest hazard quotient (HQ, from 2.18 to 2.56) for adults from 2019 to 2021, while Ni, Cr, Pb, As, and BC showed high carcinogenic risks (CR > 1.0×10-6) for adults. The HQ values of Mn and As and the CR values of Pb and As showed constant or slight upwards trends during our observations, which is in contrast to the downward trends of other HMs and PM2.5. Mn, Cr, and BC are crucial toxicants in PM2.5. A significant shrink of southern region sourcesof HMs and BCshrank suggests the increased importance of local sources. Industry, dust, and biomass burning are the major contributors to the non-carcinogenic risks, while traffic emissions and industry are the dominant contributors to the carcinogenic risks in Beijing.

Differentiating the impact of fine and coarse particulate matter on cause-specific cerebrovascular mortality: An individual-level, case-crossover study

BACKGROUND AND OBJECTIVES

Many studies suggested that short-term exposure to fine particulate matter (PM2.5) and coarse particulate matter (PM2.5-10) was linked to elevated risk of cerebrovascular disease. However, little is known about the potentially differential effects of PM2.5 and PM2.5-10 on various types of cerebrovascular disease.

METHODS

We collected individual cerebrovascular death records for all residents in Shanghai, China from 2005 to 2021. Residential daily air pollution data were predicted from a satellite model. The associations between particulate matters (PM) and cerebrovascular mortality were investigated by an individual-level, time-stratified, case-crossover design. The data was analyzed by the conditional logistic regression combined with the distributed lag model with a maximum lag of 7 days. Furthermore, we explored the effect modifications by sex, age and season.

RESULTS

A total of 388,823 cerebrovascular deaths were included. Monotonous increases were observed for mortality of all cerebrovascular diseases except for hemorrhagic stroke. A 10 μg/m3 rise in PM2.5 was related to rises of 1.35% [95% confidence interval (CI): 1.04%, 1.66%] in mortality of all cerebrovascular diseases, 1.84% (95% CI: 1.25%, 2.44%) in ischemic stroke, 1.53% (95% CI: 1.07%, 1.99%) in cerebrovascular sequelae and 1.56% (95% CI: 1.08%, 2.05%) in ischemic stroke sequelae. The excess risk estimates per each 10 μg/m3 rise in PM2.5-10 were 1.47% (95% CI: 1.10%, 1.84%), 1.53% (95% CI: 0.83%, 2.24%), 1.93% (95% CI: 1.38%, 2.49%) and 2.22% (95% CI: 1.64%, 2.81%), respectively. The associations of both pollutants with all cerebrovascular outcomes were robust after controlling for co-pollutants. The associations were greater in females, individuals > 80 years, and during the warm season.

CONCLUSIONS

Short-term exposures to both PM2.5 and PM2.5-10 may independently increase the mortality risk of cerebrovascular diseases, particularly of ischemic stroke and stroke sequelae.

Prediction of Asthma Exacerbations in Children

Asthma exacerbations are common in asthmatic children, even among those with good disease control. Asthma attacks result in the children and their parents missing school and work days; limit the patient's social and physical activities; and lead to emergency department visits, hospital admissions, or even fatal events. Thus, the prompt identification of asthmatic children at risk for exacerbation is crucial, as it may allow for proactive measures that could prevent these episodes. Children prone to asthma exacerbation are a heterogeneous group; various demographic factors such as younger age, ethnic group, low family income, clinical parameters (history of an exacerbation in the past 12 months, poor asthma control, poor adherence to treatment, comorbidities), Th2 inflammation, and environmental exposures (pollutants, stress, viral and bacterial pathogens) determine the risk of a future exacerbation and should be carefully considered. This paper aims to review the existing evidence regarding the predictors of asthma exacerbations in children and offer practical monitoring guidance for promptly recognizing patients at risk.

Understanding the Sources of Ambient Fine Particulate Matter (PM2.5) in Jeddah, Saudi Arabia

Urban air pollution is rapidly becoming a major environmental problem of public concern in several developing countries of the world. Jeddah, the second-largest city in Saudi Arabia, is subject to high air pollution that has severe implications for the health of the exposed population. Fine particulate matter (PM2.5) samples were collected for 24 h daily, during a 1-year campaign from 2013 to 2014. This study presents a detailed investigation of PM2.5 mass, chemical composition, and sources covering all four seasons of the year. Samples were analyzed for black carbon (BC), trace elements (TEs), and water-soluble ionic species (IS). The chemical compositions were statistically examined, and the temporal and seasonal patterns were characterized using descriptive analysis, correlation matrices, and elemental enrichment factor (EF). Source apportionment and source locations were performed on PM2.5 samples using the positive matrix factorization (PMF) model, elemental enrichment factor, and air-mass back trajectory analysis. The 24-h mean PM2.5 and BC concentrations ranged from 33.9 ± 9.1–58.8 ± 25 µg/m3 and 1.8 ± 0.4–2.4 ± 0.6 µg/m3, respectively. Atmospheric PM2.5 concentrations were well above the 24-h WHO guideline of 15 µg/m3, with overall results showing significant temporal and seasonal variability. EF defined two broad categories of TEs: anthropogenic (Ni, V, Cu, Zn, Cl, Pb, S, Lu, and Br), and earth-crust derived (Al, Si, Mg, K, Ca, Ti, Cr, Mn, Fe, and Sr). The five identified factors resulting from PMF were (1) fossil-fuels/oil combustion (45.3%), (2) vehicular emissions (19.1%), (3) soil/dust resuspension (15.6%), (4) industrial mixed dust (13.5%), and (5) sea-spray (6.5%). This study highlights the importance of focusing control strategies, not only on reducing PM concentration but also on the reduction of components of the PM as well, to effectively protect human health and the environment.

Compositions, Sources, and Aging Processes of Aerosol Particles during Winter Hazes in an Inland Megacity of NW China

As one of the largest inland megacities in Northwest (NW) China, Xi’an has been facing serious regional haze frequently, especially during winter. The composition of aerosols in Xi’an is highly complex due to its unique basinal topography and unique meteorological conditions. In this study, we characterized the morphology, size, and composition of individual aerosol particles collected during regional haze events at an urban site in Xi’an using Transmission Electron Microscopy (TEM) coupled with Energy-Dispersive X-ray Spectrometry (EDX). Six types of particles were identified based on their morphology and chemical composition, including organic (41.88%), sulfate (32.36%), soot (8.33%), mineral (7.91%), K-rich (5.13%), and fly ash particles (4.49%). These results demonstrate that the organic particles made a larger contribution to haze formation than the secondary inorganic particles during the sampling period. Size distribution and dominance suggest that organic and sulfate particles exert major control on the variation trends of particle size in haze. The coating thickness of organic-cored particles was about 369 nm and that of sulfate-cored particles was about 322 nm, implying that the organic particles were more aged than the sulfate particles. The results presented in this study provide further insights into understanding haze particle formation.

Cold Climate Impact on Air-Pollution-Related Health Outcomes: A Scoping Review

In cold temperatures, vehicles idle more, have high cold-start emissions including greenhouse gases, and have less effective exhaust filtration systems, which can cause up to ten-fold more harmful vehicular emissions. Only a few vehicle technologies have been tested for emissions below -7 °C (20 °F). Four-hundred-million people living in cities with sub-zero temperatures may be impacted. We conducted a scoping review to identify the existing knowledge about air-pollution-related health outcomes in a cold climate, and pinpoint any research gaps. Of 1019 papers identified, 76 were selected for review. The papers described short-term health impacts associated with air pollutants. However, most papers removed the possible direct effect of temperature on pollution and health by adjusting for temperature. Only eight papers formally explored the modifying effect of temperatures. Five studies identified how extreme cold and warm temperatures aggravated mortality/morbidity associated with ozone, particles, and carbon-monoxide. The other three found no health associations with tested pollutants and temperature. Additionally, in most papers, emissions could not be attributed solely to traffic. In conclusion, evidence on the relationship between cold temperatures, traffic-related pollution, and related health outcomes is lacking. Therefore, targeted research is required to guide vehicle regulations, assess extreme weather-related risks in the context of climate change, and inform public health interventions.

Acute effects of ambient nitrogen oxides and interactions with temperature on cardiovascular mortality in Shenzhen, China

BACKGROUND

Though inconsistent, acute effects of ambient nitrogen oxides on cardiovascular mortality have been reported. Whereas, interactive roles of temperature on their relationships and joint effects of different indicators of nitrogen oxides were less studied. This study aimed to extrapolate the independent roles of ambient nitrogen oxides and temperature interactions on cardiovascular mortality.

METHODS

Data on mortality, air pollutants, and meteorological factors in Shenzhen from 2013 to 2019 were collected. Three indicators including nitric oxide (NO), nitrogen dioxide (NO₂), and nitrogen oxides (NO_X) were studied. Adjusted generalized additive models (GAMs) were applied to analyse their associations with cardiovascular mortality in different groups.

RESULTS

The average daily concentrations of NO, NO₂, and NO_X were 11.7 μg/m³, 30.7 μg/m³, and 53.2 μg/m³, respectively. Significant associations were shown with each indicator. Cumulative effects of nitrogen oxides were more obvious than distributed lag effects. Males, population under 65 years old, and population with stroke-related condition were more susceptible to nitrogen oxides. Adverse effects of nitrogen oxides were more significant at low temperature. Impacts of NO₂ on cardiovascular mortality, and NO on stroke mortality were the most robust in the multi-pollutant models, whereas variations were shown in the other relationships.

CONCLUSIONS

Low levels of nitrogen oxides showed acute and adverse impacts and the interactive roles of temperature on cardiovascular mortality. Cumulative effects were most significant and joint effects of nitrogen oxides required more attention. Population under 65 years old and population with stroke-related health condition were susceptible, especially days at lower temperature.

The short-term associations of chronic obstructive pulmonary disease hospitalizations with meteorological factors and air pollutants in Southwest China: a time-series study

Chronic obstructive pulmonary disease (COPD) is the fourth major cause of mortality and morbidity worldwide and is projected to be the third by 2030. However, there is little evidence available on the associations of COPD hospitalizations with meteorological factors and air pollutants in developing countries/regions of Asia. In particular, no study has been done in western areas of China considering the nonlinear and lagged effects simultaneously. This study aims to evaluate the nonlinear and lagged associations of COPD hospitalizations with meteorological factors and air pollutants using time-series analysis. The modified associations by sex and age were also investigated. The distributed lag nonlinear model was used to establish the association of daily COPD hospitalizations of all 441 public hospitals in Chengdu, China from Jan/2015-Dec/2017 with the ambient meteorological factors and air pollutants. Model parameters were optimized based on quasi Akaike Information Criterion and model diagnostics was conducted by inspecting the deviance residuals. Subgroup analysis by sex and age was also performed. Temperature, relative humidity, wind and Carbon Monoxide (CO) have statistically significant and consistent associations with COPD hospitalizations. The cumulative relative risk (RR) was lowest at a temperature of 19℃ (relative humidity of 67%). Both extremely high and low temperature (and relative humidity) increase the cumulative RR. An increase of wind speed above 4 mph (an increase of CO above 1.44 mg/m³) significantly decreases (increases) the cumulative RR. Female populations were more sensitive to low temperature and high CO level; elderly (74+) populations are more sensitive to high relative humidity; younger populations (< = 74) are more susceptible to CO higher than 1.44 mg/m³. Therefore, people with COPD should avoid exposure to adverse environmental conditions of extreme temperatures and relative humidity, low wind speed and high CO level, especially for female and elderly patients who were more sensitive to extreme temperatures and relative humidity.

Pollutant-sex specific differences in respiratory hospitalization and mortality risk attributable to short-term exposure to ambient air pollution

BACKGROUND

Many studies have reported associations of individual pollutants with respiratory hospitalization and mortality based on different populations, which makes it difficult to directly compare adverse health effects among multiple air pollutants.

OBJECTIVES

The study goal is to compare acute respiratory-related hospitalization and mortality associated with short-term exposure to three ambient air pollutants and analyze differences in health risks by season, age and sex.

METHODS

Hourly measurements of air pollutants (ozone, NO₂, PM_2.5) and temperature were collected from ground-monitors for 24 cities along with daily hospitalization (1996-2012) and mortality (1984-2012) data. National associations between air pollutant and health outcome were estimated for season (warm, cold vs. year-round), age (base ≥ 1, seniors > 65), and sex (females ≥ 1 and males ≥ 1) using Bayesian hierarchical models.

RESULTS

Overall, the three air pollutants were significantly associated with acute respiratory health outcomes at different lag-days. For respiratory hospitalization, the increased risks in percent changes with 95% posterior intervals for a 10-unit increase in each pollutant were: ozone (lag1, 0.7% (0.4, 0.9)), NO₂ (lag0, 0.7% (0.1, 1.4)), and PM_2.5 (lag1, 1.3% (0.7, 1.9)). For respiratory mortality: ozone (lag2, 1.2% (0.4, 1.9)), NO₂ (lag1, 2.1% (0.6, 3.5)), and PM_2.5 (lag1, 0.6% (-1.0, 2.2)). While some differences in risk were observed by season and age group, sex-specific differences were more pronounced. Compared with males, females had a higher respiratory mortality risk (1.8% (0.6, 2.9) vs 0.5% (-0.3, 1.3)) from ozone, a higher respiratory hospitalization risk (0.9% (0.0, 1.8) vs 0.6% (-0.3, 1.4)) but lower mortality risk (1.4% (-1.0, 3.7) vs 2.2% (0.4, 4.0)) from NO₂, and a lower hospitalization risk (0.7% (-0.2, 1.7) vs 1.8% (1.0, 2.6)) from PM_2.5.

CONCLUSION

This study reports significant health effects of short-term exposure to three ambient air pollutants on respiratory hospitalization (ozone≈NO₂ < PM_2.5 per-10 unit; ozone>NO₂ ≈ PM_2.5 per-IQR) and mortality (ozone≈NO₂ > PM_2.5) in Canada. Pollutant-sex-specific differences were found, but inconclusive due to limited biological and physiological explanations. Further studies are warranted to understand the pollutant-sex specific differences.

Benefit Analysis of the 1st Spanish Air Pollution Control Programme on Health Impacts and Associated Externalities

This paper aims to provide scientific support for decision-making in the field of improving air quality by evaluating pollution reduction measures included in the current Spanish policy framework of the 1st National Air Pollution Control Programme (NAPCP). First, the health impacts of air quality are estimated by using the concentrations estimated by multiscale air quality modeling and the recommended concentration–response functions (CRF), specifically as a result of exposure to particulate matter (PM), nitrogen dioxide (NO2), and ozone (O3). Second, the associated external costs are calculated by monetization techniques. Two scenarios are analyzed: a package including existing measures (WM2030) and a package with additional measures (WAM2030). Compared with the baseline scenario, an improvement was found in the health effects of NO2, PM10, and PM2.5, while for O3 there was a slight worsening, mainly due to the increase in the O3 metric used (SOMO35), which increases over some urban areas. Despite this, the monetary valuation of the total effects on health as a whole shows external benefits due to the adoption of measures (WM2030), compared with the reference scenario (no measures) of more than € 17.5 billion and, when considering the additional measures (WAM2030), benefits of about € 58.1 billion.

Short-term effects of air pollution on daily single- and co-morbidity cardiorespiratory outpatient visits

Several studies have noted that the existence of comorbidities lead to an increase in the risk of premature mortality and morbidity. Most of the studies examining the effects of air pollution on comorbidity visits were from Northern American countries, with scarce literature from Asia. This study contributes to existing, yet limited understanding of air pollution-comorbidity by examining the effects of daily air pollutants on outpatient single morbidity and comorbid cardiorespiratory visits in Japan. A total of 1,452,505 outpatient cardiorespiratory visits were recorded among the 21 Japanese cities from 2013 to 2016. Daily outpatient cardiorespiratory visit data were obtained from a health insurance claims database managed by the Japan Medical Data Center Co., Ltd. (JMDC). A time-stratified case crossover analysis coupled with Generalized Additive Mixed Model was used to analyze the association of daily air pollutants (particulate matter 2.5 μm or less in diameter, ozone and nitrogen dioxide) on daily single (respiratory and cardiovascular) and comorbidity health outcomes. We further examined single and cumulative effects for 0-3 and 0-14 lag periods. Ozone, NO₂, and PM_2.5 were positively associated with cardiorespiratory visits in either shorter or longer lags, with more apparent comorbidity associations with NO₂ exposure. A 10-unit increase in NO₂, after adjusting for ozone, was associated with a 2.24% (95% CI: 1.34-3.15) and 6.49% (95% CI: 5.00-8.01) increase in comorbidity visit at Lag 0 (of Lag 0-3) and cumulative lag 0-3, respectively. Our results contribute to existing evidence suggesting that short-term and extended exposure to air pollution elicit health risks on cardiovascular, respiratory and comorbid clinic visits. Exposure to NO₂, in particular, was associated with increase in the risk of single and comorbidity cardiorespiratory visits. Results can be potentially utilized for both individual health (e.g. risk population health management) and health facility management (e.g. health visit influx determination).

Ambient fine particulate matter and hospital admissions for ischemic and hemorrhagic strokes and transient ischemic attack in 248 Chinese cities

Few studies have investigated the acute effects of fine particulate matter (PM_2.5) on the risk of stroke subtypes and transient ischemic attack (TIA) in low- and middle-income countries. The primary aim of this study was to assess the associations between short-term exposure to PM_2.5 and daily hospital admissions for total cerebrovascular disease, ischemic and hemorrhagic strokes, and TIA in China. A total of 8,359,162 hospital admissions in 248 Chinese cities from 2013 to 2017 were identified from the Hospital Quality Monitoring System of China. Generalized additive models with quasi-Poisson regression were used to estimate the associations in each city, and random-effect meta-analyses were conducted to combine the city-specific estimates. We found that a 10 μg/m³ increase in PM_2.5 concentration was significantly associated with a 0.19% (95% CI, 0.13% to 0.25%), 0.26% (95% CI, 0.17% to 0.35%), and 0.26% (95% CI, 0.13% to 0.38%) increase in same-day hospital admissions for total cerebrovascular disease, ischemic stroke, and TIA, respectively. In contrast, a non-significant negative association with PM_2.5 was observed for hemorrhagic stroke in the main analyses (lag 0 day), which became statistically significant when using other single-day exposures (lag 1 or 2 days) or moving average exposures (lag 0-1, 0-2, or 0-3 days) as exposure metric. These associations were robust to adjustment for other criteria air pollutants in two-pollutant models. For ischemic stroke, the effect estimates were significantly larger in people aged 65-74 years, in cool season, and in cities with lower annual average PM_2.5 concentrations. The exposure-response curves were nonlinear with a leveling off at high concentrations. These results contribute to the relatively limited literature on the PM_2.5-related risks of cerebrovascular events in low- and middle-income countries.

Systematic review and meta-analysis of case-crossover and time-series studies of short term outdoor nitrogen dioxide exposure and ischemic heart disease morbidity

BACKGROUND

Nitrogen dioxide (NO₂) is a pervasive urban pollutant originating primarily from vehicle emissions. Ischemic heart disease (IHD) is associated with a considerable public health burden worldwide, but whether NO₂ exposure is causally related to IHD morbidity remains in question. Our objective was to determine whether short term exposure to outdoor NO₂ is causally associated with IHD-related morbidity based on a synthesis of findings from case-crossover and time-series studies.

METHODS

MEDLINE, Embase, CENTRAL, Global Health and Toxline databases were searched using terms developed by a librarian. Screening, data extraction and risk of bias assessment were completed independently by two reviewers. Conflicts between reviewers were resolved through consensus and/or involvement of a third reviewer. Pooling of results across studies was conducted using random effects models, heterogeneity among included studies was assessed using Cochran's Q and I² measures, and sources of heterogeneity were evaluated using meta-regression. Sensitivity of pooled estimates to individual studies was examined using Leave One Out analysis and publication bias was evaluated using Funnel plots, Begg's and Egger's tests, and trim and fill.

RESULTS

Thirty-eight case-crossover studies and 48 time-series studies were included in our analysis. NO₂ was significantly associated with IHD morbidity (pooled odds ratio from case-crossover studies: 1.074 95% CI 1.052-1.097; pooled relative risk from time-series studies: 1.022 95% CI 1.016-1.029 per 10 ppb). Pooled estimates for case-crossover studies from Europe and North America were significantly lower than for studies conducted elsewhere. The high degree of heterogeneity among studies was only partially accounted for in meta-regression. There was evidence of publication bias, particularly for case-crossover studies. For both case-crossover and time-series studies, pooled estimates based on multi-pollutant models were smaller than those from single pollutant models, and those based on older populations were larger than those based on younger populations, but these differences were not statistically significant.

CONCLUSIONS

We concluded that there is a likely causal relationship between short term NO₂ exposure and IHD-related morbidity, but important uncertainties remain, particularly related to the contribution of co-pollutants or other concomitant exposures, and the lack of supporting evidence from toxicological and controlled human studies.

Au W, Zhao W, Xia ZL. A Systematic Review and Meta-Analysis of Short-Term Ambient Ozone Exposure and COPD Hospitalizations

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally and ozone exposure is a main cause of its disease burden. However, studies on COPD hospitalizations from short-term ambient level ozone exposure have not generated consensus results. To address the knowledge gap, comprehensive and systematic searches in several databases were conducted using specific keywords for publications up to February 14, 2020. Random-effect models were used to derive overall excess risk estimates between short-term ambient-level ozone exposure and COPD hospitalizations. The influence analyses were used to test the robustness of the results. Both meta-regression and subgroup analyses were used to explore the sources of heterogeneity and potential modifying factors. Based on the results from 26 eligible studies, the random-effect model analyses show that a 10 µg/m³ increase in maximum 8-h ozone concentration was associated with 0.84% (95% CI: 0.09%, 1.59%) higher COPD hospitalizations. The estimates were higher for warm season and multiple-day lag but lower for old populations. Results from subgroup analyses also indicate a multiple-day lag trend and bigger significant health effects during longer day intervals. Although characteristics of individual studies added modest heterogeneity to the overall estimates, the results remained robust during further analyses and exhibited no evidence of publication bias. Our systematic review and meta-analysis indicate that short-term ambient level ozone exposure was associated with increased risk of COPD hospitalizations. The significant association with multiple-day lag trend indicates that a multiple-day exposure metric should be considered for establishing ambient ozone quality and exposure standards for improvement of population health. Future investigations and meta-analysis studies should include clinical studies as well as more careful lag selection protocol.

Integrated assessment of health risk and climate effects of black carbon in the Pearl River Delta region, China

BACKGROUND

Black carbon (BC) caused by incomplete combustion of fossil and bio-fuel has a dual effect on health and climate. There is a need for systematic approaches to evaluation of health outcomes and climate impacts relevant to BC exposure.

OBJECTIVES

We propose and illustrate for the first time, to our knowledge, an integrated analysis of a region-specific health model with climate change valuation module to quantify the health and climate consequences of BC exposure.

METHODS

Based on the data from regional air pollution monitoring stations from 2013 to 2014 in the Pearl River Delta region (PRD), China, we analyzed the carcinogenic and non-carcinogenic effects and the relative risk of cause-specific mortality due to BC exposure in three typical cities of the PRD (i.e. Guangzhou, Jiangmen and Huizhou). The radiative forcing (RF) and heating rate (HR) were calculated by the Fu-Liou-Gu (FLG) plane-parallel radiation model and the conversion of empirical formula. We further connected the health and climate impacts by calculating the excess mortalities attributed to climate warming due to BC.

RESULTS

Between 2013 and 2014, carcinogenic risks of adults and children due to BC exposure in the PRD were higher than the recommended limits (1 × 10^-6 to 1 × 10^-4), resulting in an excess of 4.82 cancer cases per 10,000 adults (4.82 × 10^-4) and an excess of 1.97 cancer cases per 10,000 children (1.97 × 10^-4). Non-carcinogenic risk caused by BC was not found. The relative risks of BC exposure on mortality were higher in winter and dry season. The atmospheric RFs of BC were 26.31 W m^-2, 26.41 W m^-2, and 22.45 W m^-2 for Guangzhou, Jiangmen and Huizhou, leading to a warming of the atmosphere in the PRD. The estimated annual excess mortalities of climate warming due to BC were 5052 (95% CI: 1983, 8139), 5121 (95% CI: 2010, 8249) and 4363 (95% CI: 1712, 7032) for Guangzhou, Jiangmen and Huizhou, respectively.

CONCLUSION

Our estimates suggest that current levels of BC exposure in the PRD region posed a considerable risk to human health and the climate. Reduction of BC emission could lead to substantial health and climate co-benefits.

Evaluation of the Impact of Black Carbon on the Worsening of Allergic Respiratory Diseases in the Region of Western Serbia: A Time-Stratified Case-Crossover Study

Background and Objectives: Many epidemiological studies have shown a positive association between black carbon (BC) and the exacerbation of allergic rhinitis and allergic asthma. However, none of the studies in Serbia examined this relationship yet. The aim of this study was to examine the associations between BC and emergency department (ED) visits for allergic rhinitis and allergic asthma in the Užice region of Serbia. Materials and Methods: A time-stratified case-crossover design was applied to 523 ED visits for allergic rhinitis and asthma exacerbation that occurred in the Užice region of Serbia between 2012–2014. Data regarding ED visits were routinely collected in the Health Center of Užice. The daily average concentrations of BC were measured by automatic ambient air quality monitoring stations. Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated using conditional logistic regression adjusted for the potential confounding influence of weather variables (temperature, humidity, and air pressure). Results: Statistically significant associations were observed between ED visits for allergic rhinitis and 2-day lagged exposure to BC (OR = 3.20; CI = 1.00–10.18; p = 0.049) and allergic asthma and 3-day lagged exposure to BC (OR = 3.23; CI = 1.05–9.95; p = 0.041). Conclusion: Exposure to BC in the Užice region increases the risk of ED visits for allergic rhinitis and asthma, particularly during the heating season.

Asthma exacerbation prediction: recent insights

PURPOSE OF REVIEW

Asthma attacks are frequent in children with asthma and can lead to significant adverse outcomes including time off school, hospital admission and death. Identifying children at risk of an asthma attack affords the opportunity to prevent attacks and improve outcomes.

RECENT FINDINGS

Clinical features, patient behaviours and characteristics, physiological factors, environmental data and biomarkers are all associated with asthma attacks and can be used in asthma exacerbation prediction models. Recent studies have better characterized children at risk of an attack: history of a severe exacerbation in the previous 12 months, poor adherence and current poor control are important features which should alert healthcare professionals to the need for remedial action. There is increasing interest in the use of biomarkers. A number of novel biomarkers, including patterns of volatile organic compounds in exhaled breath, show promise. Biomarkers are likely to be of greatest utility if measured frequently and combined with other measures. To date, most prediction models are based on epidemiological data and population-based risk. The use of digital technology affords the opportunity to collect large amounts of real-time data, including clinical and physiological measurements and combine these with environmental data to develop personal risk scores. These developments need to be matched by changes in clinical guidelines away from a focus on current asthma control and stepwise escalation in drug therapy towards inclusion of personal risk scores and tailored management strategies including nonpharmacological approaches.

SUMMARY

There have been significant steps towards personalized prediction models of asthma attacks. The utility of such models needs to be tested in the ability not only to predict attacks but also to reduce them.

A Systematic Review and Meta-Analysis on Short-Term Particulate Matter Exposure and Chronic Obstructive Pulmonary Disease Hospitalizations in China

OBJECTIVE

We conducted a meta-analysis of short-term particulate matter (PM) exposure and chronic obstructive pulmonary disease (COPD) hospitalizations in China, including data from two-pollutant model.

METHODS

From PubMed and Web of Science, we selected case-crossover or time-series studies conducted in Mainland China, Hong Kong, Macao, or Taiwan to investigate the association between PM exposure and COPD hospitalizations. The meta-analysis was performed using data from both single-pollutant and two-pollutant models for PM2.5 and PM10.

RESULTS

A total of 16 studies were included in our analysis. Short-term exposure to PM2.5 and PM10 were both significantly associated with COPD hospitalizations. The results remained robust in two-pollutant model, whereas subgroup analyses demonstrated a modest heterogeneity.

CONCLUSIONS

Our review shows a small but obvious exposure-hospitalization effect in China. More studies are needed to generate the needed evidence, and advocacy is needed to stimulate initiation of solutions to the problem.

Risks of hospital admissions from a spectrum of causes associated with particulate matter pollution

Ambient particulate matter (PM) pollution has been linked to elevated hospital admissions (HAs), especially from respiratory and cardiovascular diseases. However, few studies have estimated the associations between PM pollution and HAs for a wider range of broad disease categories. This study aimed to evaluate the effects of PM with aerodynamic diameter ≤ 2.5 μm (PM_2.5) and ≤10 μm (PM₁₀) on a range of broad and specific causes of HAs in Chengdu, China during 2015-2016, using a generalized additive model (GAM). Age-, gender- and season-specific analyses were also performed on the broad categories. We further calculated the corresponding morbidity burden due to PM exposure. During the study period, the daily mean level for PM_2.5 and PM₁₀ was 57.3 μg/m³ and 94.7 μg/m³, respectively. For broad disease categories, each 10 μg/m³ increase in PM₁₀ at lag06 was associated with increments of 0.65% (95% CI: 0.32%-0.99%) in HAs from respiratory, 0.49% (95% CI: 0.04%-0.95%) from circulatory and 0.91% (95% CI: 0.15%-1.69%) from skin and subcutaneous tissue diseases. By contrast, only respiratory HAs showed a significant positive association with elevated PM_2.5 at lag06 (1.03% increase per 10 μg/m³, 95% CI: 0.50%-1.56%, p < 0.001). Increased HAs risks for several more refined specific causes within respiratory, circulatory, skin and subcutaneous tissue, nervous and genitourinary diseases were also observed. Subgroup analyses indicated that effect estimates were modified by age, gender and season. Overall, the largest morbidity burden was observed in myocardial infarction, about 11.27% (95% CI: 3.45%-18.07%) and 11.11% (95% CI: 4.07%-17.27%) of HAs for myocardial infarction could be attributable to PM_2.5 and PM₁₀ levels exceeding the WHO's air quality guidelines (24-h mean: 25 μg/m³ for PM_2.5 and 50 μg/m³ for PM₁₀). Our study suggests that both PM_2.5 and PM₁₀ increase risks of morbidity from broad range of causes of HAs in Chengdu, and result in substantial morbidity burden.

Case-crossover analysis of short-term particulate matter exposures and stroke in the health professionals follow-up study

BACKGROUND

Stroke is a leading cause of morbidity and mortality in the United States. Associations between short-term exposures to particulate matter (PM) air pollution and stroke are inconsistent. Many prior studies have used administrative and hospitalization databases where misclassification of the type and timing of the stroke event may be problematic.

METHODS

In this case-crossover study, we used a nationwide kriging model to examine short-term ambient exposure to PM10 and PM2.5 and risk of ischemic and hemorrhagic stroke among men enrolled in the Health Professionals Follow-up Study. Conditional logistic regression models were used to obtain estimates of odds ratios (OR) and 95% confidence intervals (CI) associated with an interquartile range (IQR) increase in PM2.5 or PM10. Lag periods up to 3 days prior to the stroke event were considered in addition to a 4-day average. Stratified models were used to examine effect modification by patient characteristics.

RESULTS

Of the 727 strokes that occurred between 1999 and 2010, 539 were ischemic and 122 were hemorrhagic. We observed positive statistically significant associations between PM10 and ischemic stroke (ORlag0-3 = 1.26; 95% CI: 1.03-1.55 per IQR increase [14.46 μg/m3]), and associations were elevated for nonsmokers, aspirin nonusers, and those without a history of high cholesterol. However, we observed no evidence of a positive association between short-term exposure to PM and hemorrhagic stroke or between PM2.5 and ischemic stroke in this cohort.

CONCLUSIONS

Our study provides evidence that ambient PM10 may be associated with higher risk of ischemic stroke and highlights that ischemic and hemorrhagic strokes are heterogeneous outcomes that should be treated as such in analyses related to air pollution.

The potential of omics approaches to elucidate mechanisms of biodiesel-induced pulmonary toxicity

BACKGROUND

Combustion of biodiesels in place of fossil diesel (FD) has been proposed as a method of reducing transport-related toxic emissions in Europe. While biodiesel exhaust (BDE) contains fewer hydrocarbons, total particulates and carbon monoxide than FD exhaust (FDE), its high nitrogen oxide and ultrafine particle content may still promote pulmonary pathophysiologies.

MAIN BODY

Using a complement of in vitro and in vivo studies, this review documents progress in our understanding of pulmonary responses to BDE exposure. Focusing initially on hypothesis-driven, targeted analyses, the merits and limitations of comparing BDE-induced responses to those caused by FDE exposure are discussed within the contexts of policy making and exploration of toxicity mechanisms. The introduction and progression of omics-led workflows are also discussed, summarising the novel insights into mechanisms of BDE-induced toxicity that they have uncovered. Finally, options for the expansion of BDE-related omics screens are explored, focusing on the mechanistic relevance of metabolomic profiling and offering rationale for expansion beyond classical models of pulmonary exposure.

CONCLUSION

Together, these discussions suggest that molecular profiling methods have identified mechanistically informative, novel and fuel-specific signatures of pulmonary responses to biodiesel exhaust exposure that would have been difficult to detect using traditional, hypothesis driven approaches alone.

Ambient air quality in the holy city of Makkah: A source apportionment with elemental enrichment factors (EFs) and factor analysis (PMF)

Air pollution remains a major global public health and environmental issue. We assessed the levels of PM_2.5 and delineated the major sources in Makkah, Saudi Arabia. Fine particulate matter (PM_2.5) sampling was performed from February 26, 2014-January 27, 2015 in four cycles/seasons. Samples were analyzed for black carbon (BC) and trace elements (TEs). PM_2.5 source apportionment was performed by computing enrichment factors (EFs) and positive matrix factorization (PMF). Backward-in time trajectories were used to assess the long-range transport. Significant seasonal variations in PM_2.5 were observed, Spring: 113 ± 67.1, Summer: 88.3 ± 36.4, Fall: 67.8 ± 24, and Winter: 67.6 ± 36.9 μg m^-3. The 24-h PM_2.5 exceeded the WHO (25 μg m^-3) and Saudi Arabia's (35 μg m^-3) guidelines, with an air quality index (AQI) of "unhealthy to hazardous" to human health. Most delta-C computations were below zero, indicating minor contributions from bio-mass burning. TEs were primarily Si, Ca, Fe, Al, S, K and Mg, suggesting major contributions from soil (Si, Ca, Fe, Al, Mg), and industrial and vehicular emissions (S, Ca, Al, Fe, K). EF defined two broad categories of TEs as: anthropogenic (Cu, Zn, Eu, Cl, Pb, S, Br and Lu), and earth-crust derived (Al, Si, Na, Mg, Rb, K, Zr, Ti, Fe, Mn, Sr, Y, Cr, Ga, Ca, Ni and Ce). Notably, all the anthropogenic TEs can be linked to industrial and vehicular emissions. PMF analysis defined four major sources as: vehicular emissions, 30.1%; industrial-mixed dust, 28.9%; soil/earth-crust, 24.7%; and fossil-fuels/oil combustion, 16.3%. Plots of wind trajectories indicated wind direction and regional transport as major influences on air pollution levels in Makkah. In collusion, anthropogenic emissions contributed >75% of the observed air pollution in Makkah. Developing strategies for reducing anthropogenic emissions are paramount to controlling particulate air pollution in this region.

Mortality burden attributable to PM1 in Zhejiang province, China

BACKGROUND

Limited evidence is available on the health effects of particulate matter with an aerodynamic diameter of <1 μm (PM₁), mainly due to the lack of its ground measurement worldwide.

OBJECTIVES

To identify and examine the mortality risks and mortality burdens associated with PM₁, PM_2.5, and PM₁₀ in Zhejiang province, China.

METHODS

We collected daily data regarding all-cause (stratified by age and gender), cardiovascular, stroke, respiratory, and chronic obstructive pulmonary disease (COPD) mortality, and PM₁, PM_2.5, and PM₁₀, from 11 cities in Zhejiang province, China during 2013 and 2017. We used a quasi-Poisson regression model to estimate city-specific associations between mortality and PM concentrations. Then we used a random-effect meta-analysis to pool the provincial estimates. To show the mortality burdens of PM₁, PM_2.5, and PM₁₀, we calculated the mortality fractions and deaths attributable to these PMs.

RESULTS

Daily concentrations of PM₁, PM_2.5, and PM₁₀ ranged between 0-199 μg/m³, 0-218 μg/m³, and 0-254 μg/m³, respectively; Mortality effects were significant in lag 0-2 days. The relative risks for all-cause mortality were 1.0064 (95% CI: 1.0034, 1.0094), 1.0061 (95% CI: 1.0034, 1.0089), and 1.0060 (95% CI: 1.0038, 1.0083) associated with a 10 μg/m³ increase in PM₁, PM_2.5, and PM₁₀, respectively. Age- and gender-stratified analysis shows that elderly people (aged 65+) and females are more sensitive to PMs. The mortality fractions of all-cause mortality were estimated to be 2.39% (95% CI: 1.28, 3.48) attributable to PM₁, 2.53% (95% CI: 1.42, 3.63) attributable to PM_2.5, and 3.08% (95% CI: 1.95, 4.19) attributable to PM₁₀. The ratios of attributable cause-specific deaths for PM₁/PM_2.5, PM₁/PM₁₀, and PM_2.5/PM₁₀ were higher than the ratios of their respective concentrations.

CONCLUSIONS

PM₁, PM_2.5 and PM₁₀ are risk factors of all-cause, cardiovascular, stroke, respiratory, and COPD mortality. PM₁ accounts for the vast majority of short-term PM_2.5- and PM₁₀-induced mortality. Our analyses support the notion that smaller size fractions of PM have a more toxic mortality impacts, which suggests to develop strategies to prevent and control PM₁ in China, such as to foster strict regulations for automobile and industrial emissions.

[Children exposure to PM10 on the way to school: Regulatory impact of speed regulation under 30km/h]

BACKGROUND

In Paris, air pollution is now a persistent environmental problem, especially linked to diesel cars in circulation. Exposure of children to air pollution during the journey from home to school, which takes place during peak hours of traffic, is poorly documented.

METHODS

The purpose of this work was to identify spaces less exposed to PM10 pollution. We identified spatial recurrences in the relative distribution of air pollution levels using PM10 geolocated measures taken along a fixed circuit, crossing, among others, a speed regulation zone (<30km/h). Measurements were made eight mornings between 8 and 9 a.m., in April and September 2016 in the 14th district of Paris. We obtained a hierarchical classification of spaces in terms of recurrence of relative levels of PM10 concentration.

RESULTS

The cartography of the results revealed that the spaces more exposed to high concentrations were found similarly along main roads, side streets and speed regulation<30km/h) zones. These findings suggest speed regulation is insufficient to reduce individual exposure in city streets.

CONCLUSION

Elements linked to the functional aspects of the street (commercial/residential) were apparently as important as traffic speed.

Acute effects of fine particulate matter constituents on mortality: A systematic review and meta-regression analysis

BACKGROUND

The link between PM_2.5 exposure and adverse health outcomes is well documented from studies across the world. However, the reported effect estimates vary across studies, locations and constituents. We aimed to conduct a meta-analysis on associations between short-term exposure to PM_2.5 constituents and mortality using city-specific estimates, and explore factors that may explain some of the observed heterogeneity.

METHODS

We systematically reviewed epidemiological studies on particle constituents and mortality using PubMed and Web of Science databases up to July 2015.We included studies that examined the association between short-term exposure to PM_2.5 constituents and all-cause, cardiovascular, and respiratory mortality, in the general adult population. Each study was summarized based on pre-specified study key parameters (e.g., location, time period, population, diagnostic classification standard), and we evaluated the risk of bias using the Office of Health Assessment and Translation (OHAT) Method for each included study. We extracted city-specific mortality risk estimates for each constituent and cause of mortality. For multi-city studies, we requested the city-specific risk estimates from the authors unless reported in the article. We performed random effects meta-analyses using city-specific estimates, and examined whether the effects vary across regions and city characteristics (PM_2.5 concentration levels, air temperature, elevation, vegetation, size of elderly population, population density, and baseline mortality).

RESULTS

We found a 0.89% (95% CI: 0.68, 1.10%) increase in all-cause, a 0.80% (95% CI: 0.41, 1.20%) increase in cardiovascular, and a 1.10% (95% CI: 0.59, 1.62%) increase in respiratory mortality per 10μg/m³ increase in PM_2.5. Accounting for the downward bias induced by studies of single days, the all-cause mortality estimate increased to 1.01% (95% CI: 0.81, 1.20%). We found significant associations between mortality and several PM_2.5 constituents. The most consistent and stronger associations were observed for elemental carbon (EC) and potassium (K). For most of the constituents, we observed high variability of effect estimates across cities.

CONCLUSIONS

Our meta-analysis suggests that (a) combustion elements such as EC and K have a stronger association with mortality, (b) single lag studies underestimate effects, and (c) estimates of PM_2.5 and constituents differ across regions. Accounting for PM mass in constituent's health models may lead to more stable and comparable effect estimates across different studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO: CRD42017055765.

Global Associations between Air Pollutants and Chronic Obstructive Pulmonary Disease Hospitalizations. A Systematic Review

RATIONALE

Exacerbations are key events in chronic obstructive pulmonary disease (COPD), affecting lung function decline and quality of life. The effect of exposure to different air pollutants on COPD exacerbations is not clear.

OBJECTIVES

To carry out a systematic review, examining associations between air pollutants and hospital admissions for COPD exacerbations.

METHODS

MEDLINE, Embase, BIOSIS, Science Citation Index, and the Air Pollution Epidemiology Database were searched for publications published between 1980 and September 2015. Inclusion criteria were focused on studies presenting solely a COPD outcome defined by hospital admissions and a measure of gaseous air pollutants and particle fractions. The association between each pollutant and COPD admissions was investigated in metaanalyses using random effects models. Analyses were stratified by geographical clusters for investigation of the consistency of the evidence worldwide.

MEASUREMENTS AND MAIN RESULTS

Forty-six studies were included, and results for all the pollutants under investigation showed marginal positive associations; however, the number of included studies was small, the studies had high heterogeneity, and there was evidence of small-study bias. Geographical clustering of the effects of pollution on COPD hospital admissions was evident and reduced heterogeneity significantly.

CONCLUSIONS

The most consistent association was between a 1-mg/m³ increase in carbon monoxide level and COPD-related admissions (odds ratio, 1.02; 95% confidence interval, 1.01-1.03). The heterogeneity was moderate, and there was a consistent positive association in both Europe and North America, although levels were clearly below World Health Organization guideline values. There is mixed evidence on the effects of environmental pollution on COPD exacerbations. Limitations of previous studies included the low spatiotemporal resolution of pollutants, inadequate control for confounding factors, and the use of aggregated health data that ignored personal characteristics. The need for more targeted exposure estimates in a large number of geographical locations is evident.

Effects of air pollution on respiratory hospital admissions in İstanbul, Turkey, 2013 to 2015

We examined the associations between the daily variations of air pollutants and hospital admissions for respiratory diseases in İstanbul, the largest city of Turkey. A time series analysis of counts of daily hospital admissions and outdoor air pollutants was performed using single-pollutant Poisson generalized linear model (GLM) while controlling for time trends and meteorological factors over a 3-year period (2013-2015) at different time lags (0-9 days). Effects of the pollutants (Excess Risk, ER) on current-day (lag 0) hospital admissions to the first ten days (lag 9) were determined. Data on hospital admissions, daily mean concentrations of air pollutants of PM₁₀, PM_2.5 and NO₂ and daily mean concentrations of temperature and humidity of İstanbul were used in the study. The analysis was conducted among people of all ages, but also focused on different sexes and different age groups including children (0-14 years), adults (35-44 years) and elderly (≥65 years). We found significant associations between air pollution and respiratory related hospital admissions in the city. Our findings showed that the relative magnitude of risks for an association of the pollutants with the total respiratory hospital admissions was in the order of: PM_2.5, NO₂, and PM₁₀. The highest association of each pollutant with total hospital admission was observed with PM_2.5 at lag 4 (ER = 1.50; 95% CI = 1.09-1.99), NO₂ at lag 4 (ER = 1.27; 95% CI = 1.02-1.53) and PM₁₀ at lag 0 (ER = 0.61; 95% CI = 0.33-0.89) for an increase of 10 μg/m3 in concentrations of the pollutants. In conclusion, our study showed that short-term exposure to air pollution was positively associated with increased respiratory hospital admissions in İstanbul during 2013-2015. As the first air pollution hospital admission study using GLM in İstanbul, these findings may have implications for local environmental and social policies.

Interactive effects of specific fine particulate matter compositions and airborne pollen on frequency of clinic visits for pollinosis in Fukuoka, Japan

BACKGROUND

Previous studies have revealed the interactive effects of airborne pollen and particulate matter on the daily consultations for pollinosis, but it is uncertain which compositions are responsible. This study aimed to investigate the interactive effects of specific PM_2.5 compositions and airborne pollen on the daily number of clinic visits for pollinosis in Fukuoka.

METHODS

We obtained daily data on pollen concentrations, PM_2.5 compositions, PM_2.5 mass, gaseous pollutants (SO₂, NO₂, CO, and O₃), and weather variables monitored in Fukuoka between February and April, 2002-2012. In total, 73,995 clinic visits for pollinosis were made at 10 clinics in Fukuoka Prefecture during the study period. A time-stratified case-crossover design was applied to examine the interactive effects. The concentrations of PM_2.5 and its compositions were stratified into low (<15th percentile), moderate (15th-85th percentile), and high (>85th percentile) levels, and the association between airborne pollen and daily clinic visits for pollinosis was analyzed within each level.

RESULTS

We found a significant interaction between specific PM_2.5 compositions and airborne pollen. Specifically, the odds ratio of daily clinic visits for pollinosis per interquartile increase in pollen concentration (39.8 grains/cm²) at the average cumulative lag of 0 and 2 days during high levels of non-sea-salt Ca²⁺ was 1.446 (95% CI: 1.323-1.581), compared to 1.075 (95% CI: 1.067-1.083) when only moderate levels were observed. This result remained significant when other air pollutants were incorporated into the model and was fairly persistent even when different percentile cut-off points were used. A similar interaction was found when we stratified the data according to non-sea-salt SO₄^2- levels. This finding differed from estimates made according to PM_2.5 and NO₃^- levels, which predicted that the effects of pollen were strongest in the lower levels.

CONCLUSIONS

Associations between airborne pollen and daily clinic visits for pollinosis could be enhanced by high levels of specific PM_2.5 compositions, especially non-sea-salt Ca²⁺.

Air pollution and the incidence of ischaemic and haemorrhagic stroke in the South London Stroke Register: a case-cross-over analysis

Background

Few European studies investigating associations between short-term exposure to air pollution and incident stroke have considered stroke subtypes. Using information from the South London Stroke Register for 2005–2012, we investigated associations between daily concentrations of gaseous and particulate air pollutants and incident stroke subtypes in an ethnically diverse area of London, UK.

Methods

Modelled daily pollutant concentrations based on a combination of measurements and dispersion modelling were linked at postcode level to incident stroke events stratified by haemorrhagic and ischaemic subtypes. The data were analysed using a time-stratified case–cross-over approach. Conditional logistic regression models included natural cubic splines for daily mean temperature and daily mean relative humidity, a binary term for public holidays and a sine–cosine annual cycle. Of primary interest were same day mean concentrations of particulate matter <2.5 and <10 µm in diameter (PM_2.5, PM₁₀), ozone (O₃), nitrogen dioxide (NO₂) and NO₂+nitrogen oxide (NO_X).

Results

Our analysis was based on 1758 incident strokes (1311 were ischaemic and 256 were haemorrhagic). We found no evidence of an association between all stroke or ischaemic stroke and same day exposure to PM_2.5, PM₁₀, O₃, NO₂ or NO_X. For haemorrhagic stroke, we found a negative association with PM₁₀ suggestive of a 14.6% (95% CI 0.7% to 26.5%) fall in risk per 10 µg/m³ increase in pollutant.

Conclusions

Using data from the South London Stroke Register, we found no evidence of a positive association between outdoor air pollution and incident stroke or its subtypes. These results, though in contrast to recent meta-analyses, are not inconsistent with the mixed findings of other UK studies.

Short-term Exposure to Ambient Fine Particulate Matter Increases Hospitalizations and Mortality in COPD: A Systematic Review and Meta-analysis

BACKGROUND

Many epidemiologic studies have documented variable relationships between ambient particulate matter (PM) and COPD hospitalizations and mortality in cities worldwide.

METHODS

Comprehensive and systematic searches were performed in the electronic reference databases (PubMed, EMBASE, Google Scholar, Ovid, and Web of Science) with specific search terms and selection criteria for relevant studies. Summary ORs and 95% CIs were calculated to evaluate the relationship between short-term exposure to PM with aerodynamic diameters ≤ 2.5 μm (PM2.5) and COPD hospitalizations and mortality. The sources of heterogeneity and the effect of potential confounders were explored using subgroup analyses. Study findings were analyzed using a random effects model and a fixed effects model in COPD hospitalizations and mortality, respectively.

RESULTS

The search yielded 12 studies suitable for meta-analysis of hospitalizations and six studies suitable for the mortality meta-analysis until April 15, 2015. A 10-μg/m(3) increase in daily PM2.5 (lag days 0-7) was associated with a 3.1% (95% CI, 1.6%-4.6%) increase in COPD hospitalizations and a 2.5% (95% CI, 1.5%-3.5%) increase in COPD mortality. Significant publication bias was not found in studies focusing on the relationship between short-term PM2.5 exposure and COPD hospitalizations and mortality.

CONCLUSIONS

Our combined analysis indicated that short-term exposure to a 10-μg/m(3) increment of ambient PM2.5 is associated with increased COPD hospitalizations and mortality. Further study is needed to elucidate to what extent this relationship is causal, together with other factors, and to elucidate the mechanism by which PM2.5 induces activation of cellular processes promoting COPD exacerbations.

Coarse Particulate Air Pollution Associated with Increased Risk of Hospital Admissions for Respiratory Diseases in a Tropical City, Kaohsiung, Taiwan

This study was undertaken to determine whether there was an association between coarse particles (PM₂.₅-₁₀) levels and frequency of hospital admissions for respiratory diseases (RD) in Kaohsiung, Taiwan. Hospital admissions for RD including chronic obstructive pulmonary disease (COPD), asthma, and pneumonia, and ambient air pollution data levels for Kaohsiung were obtained for the period from 2006 to 2010. The relative risk of hospital admissions for RD was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single pollutant model (without adjustment for other pollutants), increased rate of admissions for RD were significantly associated with higher coarse PM levels only on cool days (<25 °C), with a 10 µg/m³ elevation in PM₂.₅-₁₀ concentrations associated with a 3% (95% CI = 1%-5%) rise in COPD admissions, 4% (95% CI = 1%-7%) increase in asthma admissions, and 3% (95% CI = 2%-4%) rise in pneumonia admissions. No significant associations were found between coarse particle levels and the number of hospital admissions for RD on warm days. In the two-pollutant models, PM₂.₅-₁₀ levels remained significantly correlated with higher rate of RD admissions even controlling for sulfur dioxide, nitrogen dioxide, carbon monoxide, or ozone on cool days. This study provides evidence that higher levels of PM₂.₅-₁₀ enhance the risk of hospital admissions for RD on cool days.

Influence of advections of particulate matter from biomass combustion on specific-cause mortality in Madrid in the period 2004-2009

Approximately, 20 % of particulate and aerosol emissions into the urban atmosphere are of natural origin (including wildfires and Saharan dust). During these natural episodes, PM10 and PM2.5 levels usually exceed World Health Organisation (WHO) health protection thresholds. This study sought to evaluate the possible effect of advections of particulate matter from biomass fuel combustion on daily specific-cause mortality among the general population and the segment aged ≥ 75 years in Madrid. Ecological time-series study in the city of Madrid from January 01, 2004 to December 31, 2009. The dependent variable analysed was daily mortality due to natural (ICD-10:A00-R99), circulatory (ICD-10:I00-I99), and respiratory (ICD-10:J00-J99) causes in the population, both general and aged ≥ 75 years. The following independent and control variables were considered: a) daily mean PM2.5 and PM10 concentrations; b) maximum daily temperature; c) daily mean O3 and NO2 concentrations; d) advection of particulate matter from biomass combustion ( http://www.calima.ws/ ), using a dichotomous variable and e) linear trend and seasonalities. We conducted a descriptive analysis, performed a test of means and, to ascertain relative risk, fitted a model using autoregressive Poisson regression and stratifying by days with and without biomass advection, in both populations. Of the 2192 days analysed, biomass advection occurred on 56, with mean PM2.5 and PM10 values registering a significant increase during these days. PM10 had a greater impact on organic mortality with advection (RRall ages = 1.035 [1.011-1.060]; RR  ≥  75 years = 1.066 [1.031-1.103]) than did PM2.5 without advection (RRall ages = 1.017 [1.009-1.025]; RR  ≥  75 years = 1.012 [1.003-1.022]). Among specific causes, respiratory-though not circulatory-causes were associated with PM10 on days with advection in ≥ 75 year age group. PM10, rather than PM2.5, were associated with an increase in natural cause mortality on days with advection of particulate matter from biomass combustion, particularly in the ≥ 75 year age group.

Short term exposure to air pollution and stroke: systematic review and meta-analysis

OBJECTIVE

To review the evidence for the short term association between air pollution and stroke.

DESIGN

Systematic review and meta-analysis of observational studies

DATA SOURCES

Medline, Embase, Global Health, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science searched to January 2014 with no language restrictions.

ELIGIBILITY CRITERIA

Studies investigating the short term associations (up to lag of seven days) between daily increases in gaseous pollutants (carbon monoxide, sulphur dioxide, nitrogen dioxide, ozone) and particulate matter (<2.5 µm or <10 µm diameter (PM2.5 and PM10)), and admission to hospital for stroke or mortality.

MAIN OUTCOME MEASURES

Admission to hospital and mortality from stroke.

RESULTS

From 2748 articles, 238 were reviewed in depth with 103 satisfying our inclusion criteria and 94 contributing to our meta-estimates. This provided a total of 6.2 million events across 28 countries. Admission to hospital for stroke or mortality from stroke was associated with an increase in concentrations of carbon monoxide (relative risk 1.015 per 1 ppm, 95% confidence interval 1.004 to 1.026), sulphur dioxide (1.019 per 10 ppb, 1.011 to 1.027), and nitrogen dioxide (1.014 per 10 ppb, 1.009 to 1.019). Increases in PM2.5 and PM10 concentration were also associated with admission and mortality (1.011 per 10 μg/m(3) (1.011 to 1.012) and 1.003 per 10 µg/m(3) (1.002 to 1.004), respectively). The weakest association was seen with ozone (1.001 per 10 ppb, 1.000 to 1.002). Strongest associations were observed on the day of exposure with more persistent effects observed for PM(2·5).

CONCLUSION

Gaseous and particulate air pollutants have a marked and close temporal association with admissions to hospital for stroke or mortality from stroke. Public and environmental health policies to reduce air pollution could reduce the burden of stroke.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO-CRD42014009225.

Short-term effects of particulate matter constituents on daily hospitalizations and mortality in five South-European cities: results from the MED-PARTICLES project

BACKGROUND

Few recent studies examined acute effects on health of individual chemical species in the particulate matter (PM) mixture, and most of them have been conducted in North America. Studies in Southern Europe are scarce. The aim of this study is to examine the relationship between particulate matter constituents and daily hospital admissions and mortality in five cities in Southern Europe.

METHODS

The study included five cities in Southern Europe, three cities in Spain: Barcelona (2003-2010), Madrid (2007-2008) and Huelva (2003-2010); and two cities in Italy: Rome (2005-2007) and Bologna (2011-2013). A case-crossover design was used to link cardiovascular and respiratory hospital admissions and total, cardiovascular and respiratory mortality with a pre-defined list of 16 PM10 and PM2.5 constituents. Lags 0 to 2 were examined. City-specific results were combined by random-effects meta-analysis.

RESULTS

Most of the elements studied, namely EC, SO4(2-), SiO2, Ca, Fe, Zn, Cu, Ti, Mn, V and Ni, showed increased percent changes in cardiovascular and/or respiratory hospitalizations, mainly at lags 0 and 1. The percent increase by one interquartile range (IQR) change ranged from 0.69% to 3.29%. After adjustment for total PM levels, only associations for Mn, Zn and Ni remained significant. For mortality, although positive associations were identified (Fe and Ti for total mortality; EC and Mg for cardiovascular mortality; and NO3(-) for respiratory mortality) the patterns were less clear.

CONCLUSIONS

The associations found in this study reflect that several PM constituents, originating from different sources, may drive previously reported results between PM and hospital admissions in the Mediterranean area.

Short-Term Effects of Coarse Particulate Matter on Hospital Admissions for Cardiovascular Diseases: A Case-Crossover Study in a Tropical City

This study was undertaken to determine whether there was an association between coarse particles (PM2.5-10) levels and frequency of hospital admissions for cardiovascular diseases (CVD) in Kaohsiung, Taiwan. Hospital admissions for CVD, including ischemic heart disease (IHD), stroke, congestive heart failure (CHF), and arrhythmias, and ambient air pollution data levels for Kaohsiung were obtained for the period 2006-2010. The relative risk of hospital admissions for CVD was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased rates of admissions for CVD were significantly associated with higher coarse PM levels only on cool days (< 25°C), with a 10-μg/m(3) elevation in PM2.5-10 concentrations associated with a 3% (95% CI = 2-4%) rise in IHD admissions, 5% (95% CI = 4-6%) increase in stroke admissions, 3% (95% CI = 1-6%) elevation in CHF admissions, and 3% (95% CI = 0-6%) rise in arrhythmias admissions. No significant associations were found between coarse particle levels and number of hospital admissions for CVD on warm days. In the two-pollutant models, PM2.5-10 levels remained significantly correlated with higher rate of CVD admissions even controlling for sulfur dioxide, nitrogen dioxide, carbon monoxide, or ozone on cool days. Compared to the effect estimate associated with a 10-μg/m(3) increase in PM2.5 levels, effect estimates of frequency of CVD-related admissions associated with a 10-μg/m(3) rise in coarse PM levels were weaker. This study provides evidence that higher levels of PM2.5-10 enhance the risk of hospital admissions for CVD.

Air pollution, avoidance behaviour and children's respiratory health: evidence from England

Despite progress in air pollution control, concerns remain over the health impact of poor air quality. Governments increasingly issue air quality information to enable vulnerable groups to avoid exposure. Avoidance behaviour potentially biases estimates of the health effects of air pollutants. But avoidance behaviour imposes a cost on individuals and therefore may not be taken in all circumstances. This paper exploits panel data at the English local authority level to estimate the relationship between children's daily hospital emergency admissions for respiratory diseases and common air pollutants, while allowing for avoidance behaviour in response to air pollution warnings. A 1% increase in nitrogen dioxide or ozone concentrations increases hospital admissions by 0.1%. For the subset of asthma admissions - where avoidance is less costly - there is evidence of avoidance behaviour. Ignoring avoidance behaviour, however, does not result in statistically significant underestimation of the health effect of air pollution.

Outdoor fine particles and nonfatal strokes: systematic review and meta-analysis

BACKGROUND

Epidemiologic studies find that long- and short-term exposure to fine particles (PM2.5) is associated with adverse cardiovascular outcomes, including ischemic and hemorrhagic strokes. However, few systematic reviews or meta-analyses have synthesized these results.

METHODS

We reviewed epidemiologic studies that estimated the risks of nonfatal strokes attributable to ambient PM2.5. To pool risks among studies we used a random-effects model and 2 Bayesian approaches. The first Bayesian approach assumes a normal prior that allows risks to be zero, positive or negative. The second assumes a gamma prior, where risks can only be positive. This second approach is proposed when the number of studies pooled is small, and there is toxicological or clinical literature to support a causal relation.

RESULTS

We identified 20 studies suitable for quantitative meta-analysis. Evidence for publication bias is limited. The frequentist meta-analysis produced pooled risk ratios of 1.06 (95% confidence interval = 1.00-1.13) and 1.007 (1.003-1.010) for long- and short-term effects, respectively. The Bayesian meta-analysis found a posterior mean risk ratio of 1.08 (95% posterior interval = 0.96-1.26) and 1.008 (1.003-1.013) from a normal prior, and of 1.05 (1.02-1.10) and 1.008 (1.004-1.013) from a gamma prior, for long- and short-term effects, respectively, per 10 μg/m PM2.5.

CONCLUSIONS

Sufficient evidence exists to develop a concentration-response relation for short- and long-term exposures to PM2.5 and stroke incidence. Long-term exposures to PM2.5 result in a higher risk ratio than short-term exposures, regardless of the pooling method. The evidence for short-term PM2.5-related ischemic stroke is especially strong.

A case-crossover analysis of the impact of PM(2.5) on cardiovascular disease hospitalizations for selected CDC tracking states

BACKGROUND

Information is currently being collected by the CDC Environmental Public Health Tracking (EPHT) network on hospitalizations due to Acute Myocardial Infarction (AMI) and there is interest by CDC in exploring the relationship between fine particulate matter (PM2.5) and other cardiovascular (CVD) outcomes in the context of the EPHT program. The goal of this study was to assess the short term effects of daily PM(2.5) air pollution levels on hospitalizations for CVD for seven states within the CDC EPHT network (Florida, Massachusetts, New Hampshire, New Jersey, New Mexico, New York, and Washington).

METHODS

Hospitalization data was obtained for 2001-2008 admissions for circulatory disease (primary discharge diagnosis of ICD-9 codes 390-459) from data stewards in those states and included admission date, age, gender, and zip code of residence. We used CMAQ-derived predicted daily PM2.5 data as estimated by EPA at the centroid of each Census Bureau Zip Code Tabulation Area (ZCTA) and linked to zip code of patient residence. A time-stratified case-crossover study design with conditional logistic regression was used to evaluate the short-term association of PM2.5 on risk of non-elective hospitalizations for CVD. Specifically, we considered all circulatory disease, ischemic heart disease, acute myocardial infarction, heart failure, cardiac arrhythmia, cerebrovascular disease and peripheral vascular disease endpoints.

RESULTS

Data were obtained on over 7,500,000 hospitalizations for this time period. Mean annual PM2.5 exposure levels were lowest for New Mexico and Washington (6.5 μg/m3 PM2.5 and 8.4 μg/m3 PM2.5). New Jersey, New York and Massachusetts exhibited the highest annual averages for PM2.5, (12.8 μg/m3, 11.1 μg/m3 and 10.8 μg/m3), respectively. The Northeast states (Massachusetts, New Jersey, New Hampshire and New York) exhibited significant effects of PM2.5 during the cooler months across most disease categories after adjustment for ozone and maximum apparent temperature. Ischemic heart disease risk per 10 μg/m3 increase in PM2.5 varied from 1.02 to 1.05 for the cooler months. The largest lag effect was noted on lag days 0 and 1. New Mexico and Washington exhibited no cool or warm month significant effects. Although Florida showed no cooler month effects, significant increases were noted in odds ratios for the warm weather months for all outcomes except peripheral vascular disease. This study is one of the first large scale applications of linkage of hospitalization data by state with national US EPA statistically modeled air pollution data. The results demonstrate that state-wide, there are multiple cardiovascular outcomes in addition to AMI which may be impacted by particulate air pollution.

Outdoor and indoor UFP in primary schools across Barcelona

Indoor and outdoor measurements of real-time ultrafine particles (UFP; N10-700 in this study) number concentration and average diameter were collected twice at 39 primary schools located in Barcelona (Spain), with classrooms naturally ventilated under warm weather conditions. Simultaneous outdoor N concentration measurements at schools under different traffic exposures showed the important role of this source, with higher levels by 40% on average at schools near heavy traffic, highlighting thus the increased exposure of children due to urban planning decisions. A well-defined spatial pattern of outdoor UFP levels was observed. Midday increases in outdoor N levels mainly attributed to nucleation processes have been recorded both at high and low temperatures in several of the outdoor school sites (increasing levels by 15%-70%). The variation of these increases also followed a characteristic spatial pattern, pointing at schools' location as a key variable in terms of UFP load owing to the important contribution of traffic emissions. Indoor N concentrations were to some extent explained by outdoor N concentrations during school hours, together with average temperatures, related with natural ventilation. Outdoor midday increases were generally mimicked by indoor N concentrations, especially under warm temperatures. At specific cases, indoor concentrations during midday were 30%-40% higher than outdoor. The time scale of these observations evidenced the possible role of: a) secondary particle formation enhanced by indoor precursors or conditions, maybe related with surface chemistry reactions mediated by O3, and/or b) UFP from cooking activities. Significant indoor N increases were detected after school hours, probably associated with cleaning activities, resulting in indoor N concentrations up to 3 times higher than those in outdoor. A wide variability of indoor/outdoor ratios of N concentrations and mean UFP sizes was detected among schools and measurement periods, which seems to be partly associated with climatic conditions and O3 levels, although further research is required.

Ambient Coarse Particulate Matter and Human Health: A Systematic Review and Meta-Analysis

Airborne particles have been linked to increased mortality and morbidity. As most research has focused on fine particles (PM2.5), the health implications of coarse particles (PM10-2.5) are not well understood. We conducted a systematic review and meta-analysis of associations for short- and long-term PM10-2.5 concentrations with mortality and hospital admissions. Using 23 mortality and 10 hospital admissions studies, we documented suggestive evidence of increased morbidity and mortality in relation to higher short-term PM10-2.5 concentrations, with stronger relationships for respiratory than cardiovascular endpoints. Reported associations were highly heterogeneous, however, especially by geographic region and average PM10-2.5 concentrations. Adjustment for PM2.5 and publication bias resulted in weaker and less precise effect estimates, although positive associations remained for short-term PM10-2.5 concentrations. Inconsistent relationships between effect estimates for PM10-2.5 and correlations between PM10-2.5 and PM2.5 concentrations, however, indicate that PM10-2.5 associations cannot be solely explained by co-exposure to PM2.5. While suggestive evidence was found of increased mortality with long-term PM10-2.5 concentrations, these associations were not robust to control for PM2.5. Additional research is required to better understand sources of heterogeneity of associations between PM10-2.5 and adverse health outcomes.

Short-term changes in ambient particulate matter and risk of stroke: a systematic review and meta-analysis

Background

Stroke is a leading cause of death and long‐term disability in the United States. There is a well‐documented association between ambient particulate matter air pollution (PM) and cardiovascular disease morbidity and mortality. Given the pathophysiologic mechanisms of these effects, short‐term elevations in PM may also increase the risk of ischemic and/or hemorrhagic stroke morbidity and mortality, but the evidence has not been systematically reviewed.

Methods and Results

We provide a comprehensive review of all observational human studies (January 1966 to January 2014) on the association between short‐term changes in ambient PM levels and cerebrovascular events. We also performed meta‐analyses to evaluate the evidence for an association between each PM size fraction (PM_2.5, PM₁₀, PM_2.5‐10) and each outcome (total cerebrovascular disease, ischemic stroke/transient ischemic attack, hemorrhagic stroke) separately for mortality and hospital admission. We used a random‐effects model to estimate the summary percent change in relative risk of the outcome per 10‐μg/m³ increase in PM.

Conclusions

We found that PM_2.5 and PM₁₀ are associated with a 1.4% (95% CI 0.9% to 1.9%) and 0.5% (95% CI 0.3% to 0.7%) higher total cerebrovascular disease mortality, respectively, with evidence of inconsistent, nonsignificant associations for hospital admission for total cerebrovascular disease or ischemic or hemorrhagic stroke. Current limited evidence does not suggest an association between PM_2.5‐10 and cerebrovascular mortality or morbidity. We discuss the potential sources of variability in results across studies, highlight some observations, and identify gaps in literature and make recommendations for future studies.

Natural sources of atmospheric aerosols influencing air quality across Europe

Atmospheric aerosols are emitted by natural and anthropogenic sources. Contributions from natural sources to ambient aerosols vary widely with time (inter-annual and seasonal variability) and as a function of the distance to source regions. This work aims to identify the main natural sources of atmospheric aerosols affecting air quality across Europe. The origin, frequency, magnitude, and spatial and temporal variability of natural events were assessed for the years 2008 and 2009. The main natural sources of atmospheric aerosols identified were African dust, sea spray and wildfires. Primary biological particles were not included in the present work. Volcanic eruptions did not affect air quality significantly in Europe during the study period. The impact of natural episodes on air quality was significant in Southern and Western Europe (Cyprus, Spain, France, UK, Greece, Malta, Italy and Portugal), where they contributed to surpass the PM10 daily and annual limit values. In Central and Northern Europe (Germany, Austria and Latvia) the impact of these events was lower, as it resulted in the exceedance of PM daily but not annual limit values. Contributions from natural sources to mean annual PM10 levels in 2008 and 2009 ranged between 1 and 2 μg/m(3) in Italy, France and Portugal, between 1 and 4 μg/m(3) in Spain (10 μg/m(3) when including the Canary Islands), 5 μg/m(3) in UK, between 3 and 8 μg/m(3) in Greece, and reached up to 13 μg/m(3) in Cyprus. The evaluation of the number of monitoring stations per country reporting natural exceedances of the daily limit value (DLV) is suggested as a potential tool for air quality monitoring networks to detect outliers in the assessment of natural contributions. It is strongly suggested that a reference methodology for the identification and quantification of African dust contributions should be adopted across Europe.

Health impact assessment of exposure to fine particulate matter based on satellite and meteorological information

Air pollution in China, especially in the Pearl River Delta (PRD) region, has drastically increased in recent years. We modelled annual mean ground-level PM2.5 concentrations based on worldwide satellite information and meteorological data from 40 cities outside the PRD. The model of PM2.5 concentration (R = 0.845) was best explained by aerosol optical thickness (43.8%). We validated the spatial-temporal dimensions of the model and estimated that the annual mean PM2.5 concentration in PRD ranged between 22 and 65 μg m(-3). Then we used meta-analysis to obtain the pooled excess risks of mortality in China and assessed the health impacts. We found an inverse association between short-term excess risks of mortality and annual mean PM2.5 concentrations. Based on the above models and analyses, the associated excess deaths for all-cause and cardiopulmonary diseases were 3386 and 2639 respectively. The corresponding risk-standardized excess death rates were 2006 and 1069 per million people.

Risk assessment for cardiovascular and respiratory mortality due to air pollution and synoptic meteorology in 10 Canadian cities

Synoptic weather and ambient air quality synergistically influence human health. We report the relative risk of mortality from all non-accidental, respiratory-, and cardiovascular-related causes, associated with exposure to four air pollutants, by weather type and season, in 10 major Canadian cities for 1981 through 1999. We conducted this multi-city time-series study using Poisson generalized linear models stratified by season and each of six distinctive synoptic weather types. Statistically significant relationships of mortality due to short-term exposure to carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone were found, with significant modifications of risk by weather type, season, and mortality cause. In total, 61% of the respiratory-related mortality relative risk estimates were significantly higher than for cardiovascular-related mortality. The combined effect of weather and air pollution is greatest when tropical-type weather is present in the spring or summer.

Effects of dust storm events on emergency admissions for cardiovascular and respiratory diseases in Sanandaj, Iran

BACKGROUND

In recent years, increasing dust storms from western neighboring countries of Iran influenced western and central parts of the country. In this case, level of concentration of atmospheric particulate matter greater than 10 μm (PM10) remained higher for several days compared to the levels before the event. Accordingly, Suspended particulate matters of dust storms in western Iran have caused PM10 pollution in Sanandaj (capital of the Iranian province of Kurdistan) and other Iranian cities. The present study aimed to evaluate possible effects of dust storms on incidence of cardiovascular and respiratory diseases among residents of Sanandaj.

MATERIALS AND METHODS

Dust storm events defined based on the Environmental Protection Administration and Meteorological Announcements, 21 March 2009 to 21 June 2010. Data related to the dust events associated with cardiovascular and respiratory diseases were obtained from the Center for Disaster and Emergency Medicine of Sanandaj, Iran. PM10 concentration and air quality data were obtained from air quality monitoring agency of Kurdistan Provincial Directorate of Environment Protection. Daily PM10 measurements were performed automatically according to β-ray absorption. Data were statistically analyzed using SPSS and Pearson's correlation coefficient. Also, linear regression model was used to investigate the relationship between variables.

RESULTS

The average PM10 levels during dust episodes (187 μg/m(3)) were significantly higher than the other days (48.7 μg/m(3)). In addition, correlation coefficient between PM10 level and number of cardiovascular and emergency service during dust events were equal to 0.48 (P <0.05) and 0.19 (P >0.05) respectively.

CONCLUSION

Our findings showed significant increase in emergency admissions for cardiovascular and respiratory diseases during dust storms episode in Sanandaj. Although correlation between respiratory diseases and dust storm events were statistically insignificant (0.19), numbers of cardiovascular diseases were significantly correlated with dust storm events (0.48).

Short-term effects of PM2.5, PM10 and PM2.5-10 on daily mortality in The Netherlands

INTRODUCTION

Information on the relationship between levels of particulate matter (PM) smaller than 2.5 μm and mortality rates in Europe is relatively sparse because of limited availability of PM2.5 measurement data. Even less information is available on the health effects attributable to PM2.5-10, especially for North-West Europe.

OBJECTIVES

To investigate the relationship between various PM size fractions and daily mortality rates.

METHODS

Daily concentrations of PM from the Dutch National Ambient Air Quality Monitoring Network as well as all cause and cause-specific mortality rates in The Netherlands were obtained for the period 2008-2009. Poisson regression analysis using generalized additive models was used, with adjustment for potential confounding including long-term and seasonal trends, influenza incidence, meteorological variables, day of the week, and holidays. Different measures of PM (PM2.5, PM10 and PM2.5-10) were analysed.

RESULTS

PM10 and PM2.5 levels were statistically significantly (p<0.05) associated with all cause and cause-specific deaths. For example, a 10 μg/m(3) increase in previous day PM was associated with 0.8% (95% CI 0.3-1.2) excess risk in all cause mortality for PM2.5 and a 0.6% (CI 0.2-1.0) excess risk for PM10. No appreciable associations were observed for PM2.5-10. Effects of PM10, and PM2.5 were insensitive to adjustment for PM2.5-10, and vice-versa. PM10 and PM2.5 were too highly correlated to disentangle their independent effects.

CONCLUSIONS

PM10 and PM2.5 both were significantly associated with all cause and cause-specific mortality. We were unable to demonstrate significant effects for PM2.5-10, possibly due to the lower temporal variability and the higher exposure misclassification in PM2.5-10 compared to PM10 or PM2.5. The lack of effects of PM2.5-10 in our study should therefore not be interpreted as an indication that PM2.5-10 can be considered harmless.