Short-term effects of air pollution on mortality in nine French cities: a quantitative summary

Short and long-term association of exposure to ambient black carbon with all-cause and cause-specific mortality: A systematic review and meta-analysis

Black carbon (BC) is a product of incomplete or inefficient combustion and may be associated with a variety of adverse effects on human health. The objective of this study was to analyze the association between various mortalities and long-/short-term exposure to BC as an independent pollutant. In this systematic review, we searched 4 databases for original research in English up to 6^th October 2022, that investigated population-wide mortality due to BC exposure. We pooled mortality estimates and expressed them as relative risk (RR) per 10 μg/m³ increase in BC. We used a random-effect model to derive the pooled RRs. Of the 3186 studies identified, 29 articles met the eligibility criteria, including 18 long-term exposure studies and 11 short-term exposure studies. In the major meta-analysis and sensitivity analysis, positive associations were found between BC and total mortality and cause-specific disease mortalities. Among them, the short-term effects of BC on total mortality, cardiovascular disease mortality, respiratory disease mortality, and the long-term effects of BC on total mortality, ischemic heart disease mortality, respiratory disease mortality and lung cancer mortality were found to be statistically significant. The heterogeneity of the meta-analysis results was much lower for short-term studies than for long-term. Few studies were at a high risk of bias in any domain. The certainty of the evidence for most of the exposure-outcome pairs was moderate. Our study showed a significantly positive association between short-/long-term BC exposure and various mortalities. We speculate that BC has a higher adverse health effect on the respiratory system than on the cardiovascular system. This is different from the effect of PM_2.5. Therefore, more studies are needed to consider BC as a separate pollutant, and not just as a component of PM_2.5.

Health effects of exposure to sulfur dioxide, nitrogen dioxide, ozone, and carbon monoxide between 1980 and 2019: A systematic review and meta-analysis

The burden of disease attributed to the indoor exposure to sulfur dioxide (SO₂ ), nitrogen dioxide (NO₂ ), ozone (O₃ ), and carbon monoxide (CO) is not clear, and the quantitative concentration-response relationship is a prerequisite. This is a systematic review to summarize the quantitative concentration-response relationships by screening and analyzing the polled effects of population-based epidemiological studies. After collecting literature published between 1980 and 2019, a total of 19 health outcomes in 101 studies with 182 health risk estimates were recruited. By meta-analysis, the leave-one-out sensitivity analysis and Egger's test for publication bias, the robust and reliable effects were found for SO₂ (per 10 μg/m³ ) with chronic obstructive pulmonary diseases (COPD) (pooled relative risks [RRs] 1.016, 95% CI: 1.012-1.021) and cardiovascular diseases (CVD) (RR 1.012, 95%CI: 007-1.018), respectively. NO₂ (per 10 μg/m³ ) had the pooled RRs for childhood asthma, preterm birth, lung cancer, diabetes, and COPD by 1.134 (1.084-1.186), 1.079 (1.007-1.157), 1.055 (1.010-1.101), 1.019 (1.009-1.029), and 1.016 (1.012-1.120), respectively. CO (per 1 mg/m³ ) was significantly associated with Parkinson's disease (RR 1.574, 95% CI: 1.069-2.317) and CVD (RR 1.024, 95% CI: 1.011-1.038). No robust effects were observed for O₃ . This study provided evidence and basis for further estimation of the health burden attributable to the four gaseous pollutants.

UK COVID-19 lockdown: 100 days of air pollution reduction?

On the 23 March 2020, a country-wide COVID-19 lockdown was imposed on the UK. The following 100 days saw anthropogenic movements quickly halt, before slowly easing back to a "new" normality. In this short communication, we use data from official UK air-quality sensors (DEFRA AURN) and the UK Met Office stations to show how lockdown measures affected air quality in the UK. We compare the 100 days post-lockdown (23 March to 30 June 2020) with the same period from the previous 7 years. We find, as shown in numerous studies of other countries, the nitrogen oxides levels across the country dropped substantially (∼ 50%). However, we also find the ozone levels increased (∼ 10%), and the levels of sulphur dioxide more than doubled across the country. These changes, driven by a complex balance in the air chemistry near the surface, may reflect the influence of low humidity as suggested by Met Office data, and potentially, the reduction of nitrogen oxides and their interactions with multiple pollutants.

Causal Modeling in Environmental Health

The field of environmental health has been dominated by modeling associations, especially by regressing an observed outcome on a linear or nonlinear function of observed covariates. Readers interested in advances in policies for improving environmental health are, however, expecting to be informed about health effects resulting from, or more explicitly caused by, environmental exposures. The quantification of health impacts resulting from the removal of environmental exposures involves causal statements. Therefore, when possible, causal inference frameworks should be considered for analyzing the effects of environmental exposures on health outcomes.

Perception of Urban Environmental Risks and the Effects of Urban Green Infrastructures (UGIs) on Human Well-being in Four Public Green Spaces of Guangzhou, China

Cities face many challenging environmental problems that affect human well-being. Environmental risks can be reduced by Urban Green Infrastructures (UGIs). The effects of UGIs on the urban environment have been widely studied, but less attention has been given to the public perception of these effects. This paper presents the results of a study in Guangzhou, China, on UGI users' perceptions of these effects and their relationship with sociodemographic variables. A questionnaire survey was conducted in four public green spaces. Descriptive statistics, a binary logistic regression model and cross-tabulation analysis were applied on the data from 396 valid questionnaires. The results show that UGI users were more concerned about poor air quality and high temperature than about flooding events. Their awareness of environmental risks was partly in accordance with official records. Regarding the perception of the impacts of environmental risks on human well-being, elderly and female respondents with higher education levels were the most sensitive to these impacts. The respondents' perceptions of these impacts differed among the different green spaces. The effects of UGIs were well perceived and directly observed by the UGI users, but were not significantly influenced by most sociodemographic variables. Moreover, tourists had a lower perception of the impacts of environmental risks and the effects of UGI than residents did. This study provides strong support for UGIs as an effective tool to mitigate environmental risks. Local governments should consider the role of UGIs in environmental risk mitigation and human well-being with regard to urban planning and policy making.

Acute effect of multiple ozone metrics on mortality by season in 34 Chinese counties in 2013-2015

BACKGROUND

Although numerous multicentre studies have estimated the association between ozone exposure and mortality, there are currently no nationally representative multicentre studies of the ozone-mortality relationship in China.

OBJECTIVE

To investigate the effect on total (nonaccidental) and cause-specific mortality of short-term exposure to ambient ozone, and examine different exposure metrics.

METHODS

The effects of short-term exposure to ozone were analysed using various metrics (daily 1-h maximum, daily 8-h maximum and daily average) on total (nonaccidental) and cause-specific (circulatory and respiratory) mortality from 2013 to 2015 in 34 counties in 10 cities across China. We used distributed lag nonlinear models for estimating county-specific relative risk of mortality and combined the county-specific relative rates by conducting a random-effects meta-analysis.

RESULTS

In all-year analyses, a 10 μg m^-3 increase in daily average, daily 1-h maximum and daily 8-h maximum ozone at lag02 corresponded to an increase of 0.6% (95% CI: 0.33, 0.88), 0.26% (95% CI: 0.12, 0.39) and 0.37% (95% CI: 0.2, 0.55) in total (nonaccidental) mortality, 0.66% (95% CI: 0.28, 1.04), 0.31% (95% CI: 0.11, 0.51) and 0.39% (95% CI: 0.16, 0.62) in circulatory mortality, and 0.57% (95% CI: -0.09, 1.23), 0.11% (95% CI: -0.22, 0.44) and 0.22% (95% CI: -0.28, 0.72) in respiratory mortality, respectively. These estimates had a different seasonal pattern by cause of death. In general, the seasonal patterns were consistent with the times of year when ozone concentrations are highest.

CONCLUSIONS

Our findings suggest that in China, the acute effects of ozone are more closely related to daily average exposure than any other metric.

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.

"Exposure Track"-The Impact of Mobile-Device-Based Mobility Patterns on Quantifying Population Exposure to Air Pollution

Air pollution is now recognized as the world's single largest environmental and human health threat. Indeed, a large number of environmental epidemiological studies have quantified the health impacts of population exposure to pollution. In previous studies, exposure estimates at the population level have not considered spatially- and temporally varying populations present in study regions. Therefore, in the first study of it is kind, we use measured population activity patterns representing several million people to evaluate population-weighted exposure to air pollution on a city-wide scale. Mobile and wireless devices yield information about where and when people are present, thus collective activity patterns were determined using counts of connections to the cellular network. Population-weighted exposure to PM2.5 in New York City (NYC), herein termed "Active Population Exposure" was evaluated using population activity patterns and spatiotemporal PM2.5 concentration levels, and compared to "Home Population Exposure", which assumed a static population distribution as per Census data. Areas of relatively higher population-weighted exposures were concentrated in different districts within NYC in both scenarios. These were more centralized for the "Active Population Exposure" scenario. Population-weighted exposure computed in each district of NYC for the "Active" scenario were found to be statistically significantly (p < 0.05) different to the "Home" scenario for most districts. In investigating the temporal variability of the "Active" population-weighted exposures determined in districts, these were found to be significantly different (p < 0.05) during the daytime and the nighttime. Evaluating population exposure to air pollution using spatiotemporal population mobility patterns warrants consideration in future environmental epidemiological studies linking air quality and human health.

Air pollution, vascular disease and thrombosis: linking clinical data and pathogenic mechanisms

The public health burden of air pollution has been increasingly recognized over the last decades. Following the first assessed adverse effects on respiratory diseases and lung cancer, a large body of epidemiologic and clinical studies definitely documented an even stronger association of air pollution exposure with cardiovascular mortality and morbidity, particularly related to atherothrombotic (coronary and cerebrovascular) disease. Particulate matter (PM), mainly that with lower aerodynamic diameter (fine and ultrafine PM), is responsible for the most severe effects, due to its capacity to transport toxic substances deep into the lower airways. These effects have been shown to occur not only after short-term exposure to elevated concentrations of pollutants, but even after long-term relatively low levels of exposure. Vulnerable subjects (elderly persons and those with preexisting cardiopulmonary diseases) show the highest impact. Fewer and conflicting data also suggest an association with venous thromboembolism. Although not completely elucidated, a series of mechanisms have been hypothesized and tested in experimental settings. These phenomena, including vasomotor and cardiac autonomic dysfunction, hemostatic unbalance, oxidative stress and inflammatory response, have been shown to change over time and differently contribute to the short-term and long-term adverse effects of pollution exposure. Beyond environmental health policies, crucial for improving air quality and reducing the impact of such an elusive threat to public health, the recognition and assessment of the individual risk, together with specific advice, should be routinely implemented in the strategies of primary and secondary cardiovascular prevention.

Dust storms and the risk of asthma admissions to hospitals in Kuwait

OBJECTIVE

Arid areas in the Arabian Peninsula are one of the largest sources of global dust, yet there is no data on the impact of this on human health. This study aimed to investigate the impact of dust storms on hospital admissions due to asthma and all respiratory diseases over a period of 5 years in Kuwait.

METHODS

A population-based retrospective time series study of daily emergency asthma admissions and admissions due to respiratory causes in public hospitals in Kuwait was analyzed in relation to dust storm events. Dust storm days were defined as the mean daily PM(10)>200 μg/m(3) based on measurements obtained from all six monitoring sites in the country.

FINDINGS

During the five-year study period, 569 (33.6%) days had dust storm events and they were significantly associated with an increased risk of same-day asthma and respiratory admission, adjusted relative risk of 1.07 (95% CI: 1.02-1.12) and 1.06 (95% CI: 1.04-1.08), respectively. This was particularly evident among children.

CONCLUSION

Dust storms have a significant impact on respiratory and asthma admissions. Evidence is more convincing and robust compared to that from other geographical settings which highlights the importance of public health measures to protect people's health during dust storms and reduce the burden on health services due to dust events.

The Apheis project: Air Pollution and Health-A European Information System

At a time when the Health Effects Institute, Centers for Disease Control, and Environmental Protection Agency are creating an Environmental Public Health Tracking Program on Air Pollution Effects in the USA, it seemed useful to share the experience acquired since 1999 by the Apheis project (Air Pollution and Health-A European Information System), which has tracked the effects of air pollution on health in 26 European cities and continues to do so as the new Aphekom project. In particular, this paper first describes the continuing impact of air pollution on health in Europe, how the Apheis project came to be and evolved, what its main objectives and achievements have been, and how the project benefited its participants. The paper then summarizes the main learnings of the Apheis project.

Ozone and cardiovascular injury

Air pollution is increasingly recognized as an important and modifiable determinant of cardiovascular diseases in urban communities. The potential detrimental effects are both acute and chronic having a strong impact on morbidity and mortality. The acute exposure to pollutants has been linked to adverse cardiovascular events such as myocardial infarction, heart failure and life-threatening arrhythmias. The long-terms effects are related to the lifetime risk of death from cardiac causes. The WHO estimates that air pollution is responsible for 3 million premature deaths each year. The evidence supporting these data is very strong nonetheless, epidemiologic and observational data have the main limitation of imprecise measurements. Moreover, the lack of clinical experimental models makes it difficult to demonstrate the individual risk. The other limitation is related to the lack of a clear mechanism explaining the effects of pollution on cardiovascular mortality. In the present review we will explore the epidemiological, clinical and experimental evidence of the effects of ozone on cardiovascular diseases.

The pathophysiologic consequences of air pollutant exposures have been extensively investigated in pulmonary systems, and it is clear that some of the major components of air pollution (e.g. ozone and particulate matter) can initiate and exacerbate lung disease in humans [1]. It is possible that pulmonary oxidant stress mediated by particulate matter and/or ozone (O3) exposure can result in downstream perturbations in the cardiovasculature, as the pulmonary and cardiovascular systems are intricately associated, and it is well documented that specific environmental toxins (such as tobacco smoke [2]) introduced through the lungs can initiate and/or accelerate cardiovascular disease development. Indeed, several epidemiologic studies have proved that there is an association between PM and O3 and the increased incidence of cardiovascular morbidity and mortality [3]. Most of the evidence comes from studies of ambient particles concentrations. However, in Europe and elsewhere, the air pollution profile has gradually changed toward a more pronounced photochemical component. Ozone is one of the most toxic components of the photochemical air pollution mixture. Indeed, the biological basis for these observations has not been elucidated.

In the present review, the role of ozone as chemical molecule will be firstly considered. Secondly, pathogenetic mechanisms connecting the atmospheric ozone level and cardiovascular pathology will be examined. Thirdly, the literature relating hospitalization frequency, morbidity and mortality due to cardiovascular causes and ozone concentration will be studied. The correlation between ozone level and occurrence of acute myocardial infarction will be eventually discussed.

Effects of nitrogen dioxide on human health: systematic review of experimental and epidemiological studies conducted between 2002 and 2006

In order to assess health effects in humans caused by environmental nitrogen dioxide (NO(2)) a systematic review of studies in humans was conducted. MEDLINE database was searched for epidemiological studies and experiments on adverse effects of NO(2) published between 2002 and 2006. The evidence with regard to NO(2) exposure limits was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) grading system and the modified three star system. Of the 214 articles retrieved 112 fulfilled the inclusion criteria. There was limited evidence that short-term exposure to a 1-h mean value below 200 microg NO(2)/m(3) is associated with adverse health effects provided by only one study on mortality in patients with severe asthma (*2+). The effect remained after adjusting for other air pollutants. There was moderate evidence that short-term exposure below a 24-h mean value of 50 microg NO(2)/m(3) at monitor stations increases hospital admissions and mortality (**2+). Evidence was also moderate when the search was restricted to susceptible populations (children, adolescents, elderly, and asthmatics). There was moderate evidence that long-term exposure to an annual mean below 40 microg NO(2)/m(3) was associated with adverse health effects (respiratory symptoms/diseases, hospital admissions, mortality, and otitis media) provided by generally consistent findings in five well-conducted cohort and case-control studies with some shortcomings in the study quality (**2+). Evidence was also moderate when the search was restricted to studies in susceptible populations (children and adolescents) and for the combination with other air pollutants. The most frequent reasons for decreased study quality were potential misclassification of exposure and selection bias. None of the high-quality observational studies evaluated was informative for the key questions due to the choice of the dose parameter (e.g., 1-week mean) and exposure levels above the limit values. Inclusion of study designs unlisted in the SIGN grading system did not bring additional evidence regarding exposures below the current air quality limit values for NO(2). As several recent studies reported adverse health effects below the current exposure limits for NO(2) particularly among susceptible populations regarding long-term exposure further research is needed. Apart from high-quality epidemiological studies on causality and the interaction of NO(2) with other air pollutants there is a need for double-blinded randomized cross-over studies among susceptible populations for further evaluation of the short-term exposure limits.

Cardiovascular effects of air pollution

Air pollution is a heterogeneous mixture of gases, liquids and PM (particulate matter). In the modern urban world, PM is principally derived from fossil fuel combustion with individual constituents varying in size from a few nanometres to 10 μm in diameter. In addition to the ambient concentration, the pollution source and chemical composition may play roles in determining the biological toxicity and subsequent health effects. Nevertheless, studies from across the world have consistently shown that both short- and long-term exposures to PM are associated with a host of cardiovascular diseases, including myocardial ischaemia and infarctions, heart failure, arrhythmias, strokes and increased cardiovascular mortality. Evidence from cellular/toxicological experiments, controlled animal and human exposures and human panel studies have demonstrated several mechanisms by which particle exposure may both trigger acute events as well as prompt the chronic development of cardiovascular diseases. PM inhaled into the pulmonary tree may instigate remote cardiovascular health effects via three general pathways: instigation of systemic inflammation and/or oxidative stress, alterations in autonomic balance, and potentially by direct actions upon the vasculature of particle constituents capable of reaching the systemic circulation. In turn, these responses have been shown to trigger acute arterial vasoconstriction, endothelial dysfunction, arrhythmias and pro-coagulant/thrombotic actions. Finally, long-term exposure has been shown to enhance the chronic genesis of atherosclerosis. Although the risk to one individual at any single time point is small, given the prodigious number of people continuously exposed, PM air pollution imparts a tremendous burden to the global public health, ranking it as the 13th leading cause of morality (approx. 800000 annual deaths).

A 10-year time-series analysis of respiratory and cardiovascular morbidity in Nicosia, Cyprus: the effect of short-term changes in air pollution and dust storms

BACKGROUND

To date, a substantial body of research has shown adverse health effects of short-term changes in levels of air pollution. Such associations have not been investigated in smaller size cities in the Eastern Mediterranean. A particular feature in the region is dust blown from the Sahara a few times a year resulting in extreme PM10 concentrations. It is not entirely clear whether such natural phenomena pose the same risks.

METHODS

The effect of changes in daily levels of particulate matter (PM10) and ozone (O3) on hospitalization for all, cardiovascular and respiratory causes in the two hospitals in Nicosia during 1 January 1995 and 30 December 2004 was investigated using generalized additive Poisson models after controlling for long- and short-term patterns as well as for the effect of weather. Meteorological records were reviewed to identify dust-storm days and analyses were repeated to quantify their effect on cardio-respiratory morbidity.

RESULTS

For every 10 microg/m3 increase in daily average PM10 concentrations, there was a 0.9% (95%CI: 0.6%, 1.2%) increase in all-cause and 1.2% (95%CI: -0.0%, 2.4%) increase in cardiovascular admissions. With respect to respiratory causes, an effect was observed only in the warm months. No lagged effects with levels of PM10 were observed. In contrast, positive associations with levels of ozone were only observed the two days prior to admission. These appeared stronger for cardiovascular causes and independent of the effect of PM. All-cause and cardiovascular admissions were 4.8% (95%CI: 0.7%, 9.0%) and 10.4% (95%CI: -4.7%, 27.9%) higher on dust storm days respectively. In both cases the magnitude of effect was comparable to that seen on the quartile of non-storm days with the highest levels of PM10.

CONCLUSION

We observed an increased risk of hospitalization at elevated levels of particulate matter and ozone generally consistent with the magnitude seen across several European cities. We also observed an increased risk of hospitalization on dust storm days, particularly for cardiovascular causes. While inference from these associations is limited due to the small number of dust storm days in the study period, it would appear imperative to issue health warnings for these natural events, particularly directed towards vulnerable population groups.

Air quality risk assessment and management

This article provides (1) a synthesis of the literature on the linkages between air pollution and human health, (2) an overview of quality management approaches in Canada, the United States, and the European Union (EU), and (3) future directions for air quality research. Numerous studies examining short-term effects of air pollution show significant associations between ambient levels of particulate matter (PM) and other air pollutants and increases in premature mortality and hospitalizations for cardiovascular and respiratory illnesses. Several well-designed epidemiological studies confirmed the adverse long-term effects of PM on both mortality and morbidity. Epidemiological studies also document significant associations between ozone (O3), sulfur (SO2), and nitrogen oxides (NO(x)) and adverse health outcomes; however, the effects of gaseous pollutants are less well documented. Subpopulations that are more susceptible to air pollution include children, the elderly, those with cardiorespiratory disease, and socioeconomically deprived individuals. Canada-wide standards for ambient air concentrations of PM2.5 and O3 were set in 2000, providing air quality targets to be achieved by 2010. In the United States, the Clean Air Act provides the framework for the establishment and review of National Ambient Air Quality Standards for criteria air pollutants and the establishment of emissions standards for hazardous air pollutants. The 1996 European Union's enactment of the Framework Directive for Air Quality established the process for setting Europe-wide limit values for a series of pollutants. The Clean Air for Europe program was established by the European Union to review existing limit values, emission ceilings, and abatement protocols, as set out in the current legislation. These initiatives serve as the legislative framework for air quality management in North America and Europe.

Short-term exposure to air pollution and inflammation-sensitive biomarkers

OBJECTIVES

To evaluate the effect of short-term exposure to air pollutants on inflammation-sensitive biomarkers in apparently healthy individuals.

METHODS

We enrolled all participants from The Tel-Aviv Sourasky Medical Center inflammation survey held between 2003 and 2006, excluding participants with an acute or chronic inflammatory disease, pregnancy, steroidal or nonsteroidal treatment, or a recent invasive procedure. Additional subjects were excluded for living more than 11km from the nearest air pollution monitoring station. Analysis was performed separately for men and women. Linear regression models were fitted for each inflammatory variable against air pollutant variables (particulate matter under 10microm, sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone) for increasing lag times of up to 7 days, and adjusted for all possible and known confounding parameters.

RESULTS

The study population comprised 3659 individuals (2203 males and 1456 females). We found a statistically significant negative correlation in the male population between air pollutants, mainly NO2, SO2, and CO, and fibrinogen in several lag days. A positive correlation was found for PM10 at day 7. No such correlation was found for CRP and WBC, or for the female population.

CONCLUSION

Our findings do not support the potential link between short-term exposure to air pollution and enhanced inflammation as a possible explanation for increased cardiovascular morbidity. Additional large-scale population-based studies with good methodological design are needed in order to clarify this issue.

Short-term effects of air pollution on cardiovascular diseases: outcomes and mechanisms

The effects of air pollution on health have been intensively studied in recent years. Acute exposure to environmental pollutants such as particulate and gaseous matters (carbon monoxide, nitrogen oxides, sulphur dioxide and ozone) was associated with an increased rate of events and mortality because of cardiovascular diseases. These effects were investigated in short-term studies, which related day-to-day variations in air pollution to disease, and in long-term studies, which have followed cohorts of exposed individuals over time. The evidence from the literature on the short-term cardiovascular effects of air pollutants is discussed from clinical and mechanistic points of view.

The relation between temperature, ozone, and mortality in nine French cities during the heat wave of 2003

BACKGROUND

During August 2003, record high temperatures were observed across Europe, and France was the country most affected. During this period, elevated ozone concentrations were measured all over the country. Questions were raised concerning the contribution of O3 to the health impact of the summer 2003 heat wave.

METHODS

We used a time-series design to analyze short-term effects of temperature and O3 pollution on mortality. Counts of deaths were regressed on temperatures and O3 levels, controlling for possible confounders: long-term trends, season, influenza outbreaks, day of the week, and bank holiday effects. For comparison with previous results of the nine cities, we calculated pooled excess risk using a random effect approach and an empirical Bayes approach.

FINDINGS

For the nine cities, the excess risk of death is significant (1.01% ; 95% confidence interval, 0.58-1.44) for an increase of 10 microg/m3 in O3 level. For the 3-17 August 2003 period, the excess risk of deaths linked to O3 and temperatures together ranged from 10.6% in Le Havre to 174.7% in Paris. When we compared the relative contributions of O3 and temperature to this joint excess risk, the contribution of O3 varied according to the city, ranging from 2.5% in Bordeaux to 85.3% in Toulouse.

INTERPRETATION

We observed heterogeneity among the nine cities not only for the joint effect of O3 and temperatures, but also for the relative contribution of each factor. These results confirmed that in urban areas O3 levels have a non-negligible impact in terms of public health.

Apheis: Health impact assessment of long-term exposure to PM(2.5) in 23 European cities

INTRODUCTION

Apheis aims to provide European decision makers, environmental-health professionals and the general public with up-to-date and easy-to-use information on air pollution (AP) and public health (PH). In the Apheis-3 phase we quantified the PH impact of long-term exposure to PM(2.5) (particulate matter < 2.5 microm) in terms of attributable number of deaths and the potential gain in life expectancy in 23 European cities.

METHODS

We followed the World Health Organization (WHO) methodology for Health Impact Assessment (HIA) and the Apheis guidelines for data collection and analysis. We used the programme created by PSAS-9 for attributable-cases calculations and the WHO software AirQ to estimate the potential gain in life expectancy. For most cities, PM(2.5) levels were calculated from PM10 measurements using a local or European conversion factor.

RESULTS

The HIA estimated that 16,926 premature deaths from all causes, including 11,612 cardiopulmonary deaths and 1901 lung-cancer deaths, could be prevented annually if long-term exposure to PM(2.5 )levels were reduced to 15 microg/m3 in each city. Equivalently, this reduction would increase life expectancy at age 30 by a range between one month and more than two years in the Apheis cities.

CONCLUSIONS

In addition to the number of attributable cases, our HIA has estimated the potential gain in life expectancy for long-term exposure to fine particles, contributing to a better quantification of the impact of AP on PH in Europe.

Short-Term Effects of Ambient Particles on Cardiovascular and Respiratory Mortality

BACKGROUND

Particulate air pollution is associated with increased mortality. There is a need for European results from multicountry databases concerning cause-specific mortality to obtain more accurate effect estimates.

METHODS

We report the estimated effects of ambient particle concentrations (black smoke and particulate matter less than 10 mum [PM10]) on cardiovascular and respiratory mortality, from 29 European cities, within the Air Pollution and Health: a European Approach (APHEA2) project. We applied a 2-stage hierarchical modeling approach assessing city-specific effects first and then overall effects. City characteristics were considered as potential effect modifiers.

RESULTS

An increase in PM10 by 10 microg/m (lag 0 + 1) was associated with increases of 0.76% (95% confidence interval = 0.47 to 1.05%) in cardiovascular deaths and 0.58% (0.21 to 0.95%) in respiratory deaths. The same increase in black smoke was associated with increases of 0.62% (0.35 to 0.90%) and 0.84% (0.11 to 1.57%), respectively.

CONCLUSIONS

These effect estimates are appropriate for health impact assessment and standard-setting procedures.

Impact of the 2003 heatwave on all-cause mortality in 9 French cities

BACKGROUND

A heatwave occurred in France in August 2003, with an accompanying excess of all-cause mortality. This study quantifies this excess mortality and investigates a possible harvesting effect in the few weeks after the heatwave.

METHODS

A time-series study using a Poisson regression model with regression splines to control for nonlinear confounders was used to analyze the correlation between heatwave variable and mortality in 9 French cities.

RESULTS

After controlling for long-term and seasonal time trends and the usual effects of temperature and air pollution, we estimated that 3,096 extra deaths resulted from the heatwave. The maximum daily relative risk of mortality during the heatwave (compared with expected deaths at that time of year) ranged from 1.16 in Le Havre to 5.00 in Paris. There was little evidence of mortality displacement in the few weeks after the heatwave, with an estimated deficit of 253 deaths at the end of the period.

CONCLUSIONS

The heatwave in France during August 2003 was associated with a large increase in the number of deaths. The impact estimated using a time-series design was consistent with crude previous estimates of the impact of the heatwave. This finding suggests that neither air pollution nor long-term and seasonal trends confounded previous estimates. There was no evidence to suggest that the extras deaths associated with the heatwave were simply brought forward in time.

A Meta-Analysis of Time-Series Studies of Ozone and Mortality With Comparison to the National Morbidity, Mortality, and Air Pollution Study

BACKGROUND

Although many time-series studies of ozone and mortality have identified positive associations, others have yielded null or inconclusive results, making the results of these studies difficult to interpret.

METHODS

We performed a meta-analysis of 144 effect estimates from 39 time-series studies, and estimated pooled effects by lags, age groups, cause-specific mortality, and concentration metrics. We compared results with pooled estimates from the National Morbidity, Mortality, and Air Pollution Study (NMMAPS), a time-series study of 95 large U.S. urban centers from 1987 to 2000.

RESULTS

Both meta-analysis and NMMAPS results provided strong evidence of a short-term association between ozone and mortality, with larger effects for cardiovascular and respiratory mortality, the elderly, and current-day ozone exposure. In both analyses, results were insensitive to adjustment for particulate matter and model specifications. In the meta-analysis, a 10-ppb increase in daily ozone at single-day or 2-day average of lags 0, 1, or 2 days was associated with an 0.87% increase in total mortality (95% posterior interval = 0.55% to 1.18%), whereas the lag 0 NMMAPS estimate is 0.25% (0.12% to 0.39%). Several findings indicate possible publication bias: meta-analysis results were consistently larger than those from NMMAPS; meta-analysis pooled estimates at lags 0 or 1 were larger when only a single lag was reported than when estimates for multiple lags were reported; and heterogeneity of city-specific estimates in the meta-analysis were larger than with NMMAPS.

CONCLUSIONS

This study provides evidence of short-term associations between ozone and mortality as well as evidence of publication bias.

Ozone Air Pollution Is Associated With Acute Myocardial Infarction

BACKGROUND

Despite the diversity of the studied health outcomes, types and levels of pollution, and various environmental settings, there is substantial evidence for a positive link between urban air pollution and cardiovascular diseases. The objective of this study was to test the associations between air pollutants and the occurrence of acute myocardial infarction (AMI).

METHODS AND RESULTS

Pollutant concentrations (SO2, NO2, and O3) were measured hourly as part of the automated air quality network. Since 1985, an AMI registry (the Toulouse MONICA Project) has been collecting data in the southwest of France. All cases of AMI and sudden and probable cardiac deaths are recorded for subjects 35 to 64 years of age. We studied the short-term exposure effect of pollution on the risk of AMI (from January 1, 1997, to June 30, 1999) using a case-crossover design method. We performed a conditional logistic regression analysis to calculate relative risks (RRs) and their 95% CIs. After adjustment for temperature, relative humidity, and influenza epidemics, the RRs (for an increase of 5 microg/m3 of O3 concentration) for AMI occurrence were significant for the current-day and 1-day-lag measurements (RR, 1.05; 95% CI, 1.01 to 1.08; P=0.009; and RR, 1.05; 95% CI, 1.01 to 1.09; P=0.007, respectively). Subjects 55 to 64 years of age with no personal history of ischemic heart disease were the most susceptible to develop an AMI (RR, 1.14; 95% CI, 1.06 to 1.23). NO2 and SO2 exposures were not significantly associated with the occurrence of AMI.

CONCLUSIONS

Observational data confirm that short-term O3 exposure within a period of 1 to 2 days is related to acute coronary events in middle-aged adults without heart disease, whereas NO2 and SO2 are not.

Ozone and short-term mortality in 95 US urban communities, 1987-2000

CONTEXT

Ozone has been associated with various adverse health effects, including increased rates of hospital admissions and exacerbation of respiratory illnesses. Although numerous time-series studies have estimated associations between day-to-day variation in ozone levels and mortality counts, results have been inconclusive.

OBJECTIVE

To investigate whether short-term (daily and weekly) exposure to ambient ozone is associated with mortality in the United States.

DESIGN AND SETTING

Using analytical methods and databases developed for the National Morbidity, Mortality, and Air Pollution Study, we estimated a national average relative rate of mortality associated with short-term exposure to ambient ozone for 95 large US urban communities from 1987-2000. We used distributed-lag models for estimating community-specific relative rates of mortality adjusted for time-varying confounders (particulate matter, weather, seasonality, and long-term trends) and hierarchical models for combining relative rates across communities to estimate a national average relative rate, taking into account spatial heterogeneity.

MAIN OUTCOME MEASURE

Daily counts of total non-injury-related mortality and cardiovascular and respiratory mortality in 95 large US communities during a 14-year period.

RESULTS

A 10-ppb increase in the previous week's ozone was associated with a 0.52% increase in daily mortality (95% posterior interval [PI], 0.27%-0.77%) and a 0.64% increase in cardiovascular and respiratory mortality (95% PI, 0.31%-0.98%). Effect estimates for aggregate ozone during the previous week were larger than for models considering only a single day's exposure. Results were robust to adjustment for particulate matter, weather, seasonality, and long-term trends.

CONCLUSIONS

These results indicate a statistically significant association between short-term changes in ozone and mortality on average for 95 large US urban communities, which include about 40% of the total US population. The findings indicate that this widespread pollutant adversely affects public health.

Retentissement de la pollution atmosphérique sur la santé

OBJECTIVES

To quantify the short term effects of air pollution on mortality and hospitalisation for cardiovascular or respiratory disorders in the nine French cities (Bordeaux, Le Havre, Lille, Lyon, Marseille, Paris, Rouen, Strasbourg and Toulouse) of the Surveillance Air et Santé program.

METHODS

Data were available on mortality and hospitalisation were available, respectively, from 1990 to 1997 and 1995 to 1999. Exposure data were the concentrations of sulphur dioxide, particles with a diameter of less than or equal to 10 mm, black smoke, nitrogen dioxide, ozone, and carbon monoxide. The analysis assessed the relationships, in each of the cities, between the daily numbers of deaths and hospitalisations and the daily levels of polluting agents, taking into account confounding factors. A combined relative risk was calculated for all the cities. The number of deaths and hospitalisations attributable to air pollution was then estimated for each of the cities, based on the relative risk.

RESULTS

Significant relationships were found for mortality, from whatever cause, and for hospitalisations for respiratory disorders in children aged under 15. If the levels of air pollution were reduced to 10 microg/m3 in the nine cities, 2800 premature deaths and 750 hospitalisations for respiratory disorders in children would be avoided, every year.

CONCLUSION

Today, it is possible to assess the benefits of reducing air pollution in terms of health in the short term. These analyses would provide a sanitary dimension to the strategies for the reduction of urban pollution on local and European level.

Apheis: public health impact of PM10 in 19 European cities

STUDY OBJECTIVE

Apheis is a public health surveillance system that aims to provide European, national, regional, and local decision makers, environmental health professionals, and the general public with up to date and easy to use information on air pollution and public health. This study presents the health impact assessment done in 19 cities of Western and Eastern European countries.

DESIGN

Apheis developed guidelines for gathering and analysing data on air pollution and the impact on public health. Apheis has analysed the acute and chronic effects of fine particles on premature mortality using the estimates developed by Aphea2 study and two American cohort studies. This health impact assessment was performed for different scenarios on the health benefits of reducing levels of particles less than 10 microm in size (PM(10)).

MAIN RESULTS

PM(10) concentrations were measured in 19 cities (range: 14-73 microg/m(3)). The population covered in this health impact assessment includes nearly 32 million inhabitants. The age standardised mortality rates (per 100 000 people) range from 456 in Toulouse to 1127 in Bucharest. Reducing long term exposure to PM(10) concentrations by 5 microg/m(3) would have "prevented" between 3300 and 7700 early deaths annually, 500 to 1000 of which are associated with short term exposure.

CONCLUSIONS

Apheis shows that current levels of air pollution in urban Europe have a non-negligible impact on public health, and that preventive measures could reduce this impact, even in cities with low levels of air pollution.

[Air pollution and cardiovascular toxicity: known risks]

SUBJECT

Review of studies about epidemiological and physiopathological knowledge of ambient air particles short-term cardio-vascular effects. CURRENTS AND STRONG POINTS: Many studies, in contrasted countries for pollution's sources, meteorological conditions or socio-demographical characteristics, have shown health effects due to ambient air particles. After having studied mainly the respiratory effects of particulate air pollution, epidemiologists are now interested in the cardio-vascular effects of ambient air particles. In fact, serious effects seem to exist in fragile people which can get to emergency department visits, hospitalisation and even death. In addition, studies have shown less serious effects, but likely to be frequent (cardiac symptoms, and stoppages for cardio-vascular causes, notably). The exact mechanism by which particles have cardio-vascular adverse health effects is unknown, but experimental and epidemiological studies have led to several hypotheses: local pulmonary effects seem to be followed by systemic effects, which would be responsible for effects on the electrical activity of the heart through cardiac autonomic dysfunction and effects on the blood supply to the heart. The objective of this work is to summarise epidemiological and physiopathological knowledge about the cardio-vascular effects of ambient air particles.

PROSPECTS AND PROJECTS

To evaluate the real importance of cardio-vascular effects due to particulate air pollution and to identify their exact mechanism, a more precise knowledge of detailed causes of deaths and hospitalisations and a better knowledge of less serious effects, but likely to be frequent, is necessary. Equally, a detailed identification of fragile people is essential for developing preventive actions.

Difference in the relation between daily mortality and air pollution among elderly and all-ages populations in southwestern France

Numerous time series studies around the world have reported an association between mortality and particulate air pollution. We investigated the distribution over time of effect of air pollution on short-term mortality among subjects aged 65 years and older and of all ages in Bordeaux, France. Statistical analysis was based on generalized additive models using either loess or penalized spline smoothing. Our study found a significant positive association between air pollution and all nonaccidental mortality and specific mortality in both group of population (all ages and elderly) with a greater effect among the elderly, particularly for respiratory mortality. For this case, we observed a greater effect according to distributed lag models (0-5 days) among the elderly, with an estimated increase of 9.2% in the daily number of deaths for 10 microg/m(3) of daily black smoke [95% CI, 3.4-15.3]. These results contribute to the efforts made to understand how air pollution promotes adverse health effects and to identify susceptible subgroups.