Particulate air pollution and susceptibility to the development of pulmonary tuberculosis disease in North Carolina: an ecological study

Although Mycobacterium tuberculosis is the causative agent of pulmonary tuberculosis (PTB), environmental factors may influence disease progression. Ecologic studies conducted in countries outside the USA with high levels of air pollution and PTB have suggested a link between active disease and ambient air pollution. The present investigation is the first to examine the ambient air pollution-PTB association in a country, where air pollution levels are comparatively lower. We used Poisson regression models to examine the association of outdoor air pollutants, PM₁₀ and PM_2.5 with rates of PTB in North Carolina residents during 1993–2007. Results suggest a potential association between long-term exposure to particulate matter (PM) and PTB disease. In view of the high levels of air pollution and high rates of PTB worldwide, a potential association between ambient air pollution and tuberculosis warrants further study.     

A spatially disaggregated time-series analysis of the short-term effects of particulate matter exposure on mortality in Chennai, India

The global burden of disease due to air pollution is concentrated in the rapidly developing counties of Asia, but a recent meta-analysis found that relatively few studies on short-term exposure to air pollution and mortality have been performed in these countries, including India. Local evidence on the effects of short-term exposures to air pollutants on mortality and cardio-respiratory morbidity in Asia would reduce the uncertainties in current impact estimations and facilitate effective public policy responses to a deteriorating air pollution situation in South Asia. Here, we report the results from one of the first of such studies in metropolitan Chennai, India, conducted as part of a co-ordinated multi-city time-series initiative in India aimed at estimating the effect of short-term exposure to particulate matter ≤10 μm in aerodynamic diameter (PM₁₀) on all-cause mortality. The studies in Indian cities (Chennai, Delhi and Ludhiana) were part of a larger multi-city effort in Asia, co-ordinated by The Health Effects Institute (Boston, MA, USA) under their program for Public health and Air Pollution in Asia (PAPA). An important study output included the development of methodological refinements to overcome the limitations of routinely collected data in terms of missing measurements, small footprints of air pollution monitors and incomplete address information on death records. We used data on ambient air quality and all-cause mortality collected over the period 2002–2004. Exposures and health outcomes were disaggregated at the level of individual city zones and subsequently used in quasi-Poisson generalized additive models with smooth functions of time, temperature and relative humidity. Our model estimated a 0.44% (95% confidence interval?0.17–0.71) increase in mortality per 10 μg/m³ increase in daily average concentrations of PM₁₀, which is comparable to estimates from other PAPA cities and previous studies in North America and Europe. The results from PAPA studies in India, while preliminary, serve to strengthen the local evidence base for air pollution-related health effects that is imminently needed for better air quality management, while adding valuable information from India to the global repository of evidence.     

Impact of improved cookstoves on indoor air pollution and adverse health effects among Honduran women

Elevated indoor air pollution levels due to the burning of biomass in developing countries are well established. Few studies have quantitatively assessed air pollution levels of improved cookstoves and examined these measures in relation to health effects. We conducted a cross-sectional survey among 79 Honduran women cooking with traditional or improved cookstoves. Carbon monoxide and fine particulate matter (PM_2.5) levels were assessed via indoor and personal monitoring. Pulmonary function and respiratory symptoms were ascertained. Finger-stick blood spot samples were collected to measure C-reactive protein (CRP) concentrations. The use of improved stoves was associated with 63% lower levels of personal PM_2.5, 73% lower levels of indoor PM_2.5, and 87% lower levels of indoor carbon monoxide as compared to traditional stoves. Women using traditional stoves reported symptoms more frequently than those using improved stoves. There was no evidence of associations between cookstove type or air quality measures with lung function or CRP.     

Season, sex, age, and education as modifiers of the effects of outdoor air pollution on daily mortality in Shanghai, China: The Public Health and Air Pollution in Asia (PAPA) Study

BACKGROUND: Various factors can modify the health effects of outdoor air pollution. Prior findings about modifiers are inconsistent, and most of these studies were conducted in developed countries. OBJECTIVES: We conducted a time-series analysis to examine the modifying effect of season, sex, age, and education on the association between outdoor air pollutants [particulate matter < 10 microm in aerodynamic diameter (PM(10)), sulfur dioxide, nitrogen dioxide, and ozone] and daily mortality in Shanghai, China, using 4 years of daily data (2001-2004). METHODS: Using a natural spline model to analyze the data, we examined effects of air pollution for the warm season (April-September) and cool season (October-March) separately. For total mortality, we examined the association stratified by sex and age. Stratified analysis by educational attainment was conducted for total, cardiovascular, and respiratory mortality. RESULTS: Outdoor air pollution was associated with mortality from all causes and from cardiorespiratory diseases in Shanghai. An increase of 10 mug/m(3) in a 2-day average concentration of PM(10), SO(2), NO(2), and O(3) corresponds to increases in all-cause mortality of 0.25% [95% confidence interval (CI), 0.14-0.37), 0.95% (95% CI, 0.62-1.28), 0.97% (95% CI, 0.66-1.27), and 0.31% (95% CI, 0.04-0.58), respectively. The effects of air pollutants were more evident in the cool season than in the warm season, and females and the elderly were more vulnerable to outdoor air pollution. Effects of air pollution were generally greater in residents with low educational attainment (illiterate or primary school) compared with those with high educational attainment (middle school or above). CONCLUSIONS: Season, sex, age, and education may modify the health effects of outdoor air pollution in Shanghai. These findings provide new information about the effects of modifiers on the relationship between daily mortality and air pollution in developing countries and may have implications for local environmental and social policies.     

Air pollution and hospital admissions for cardiovascular disease in Taipei, Taiwan

This study was undertaken to determine whether there is an association between air pollutants levels and hospital admissions for cardiovascular diseases (CVD) in Taipei, Taiwan. Hospital admissions for CVD and ambient air pollution data for Taipei were obtained for the period 1997-2001. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the one-pollutant models, on warm days (>or=20 degrees C) statistically significant positive associations were found between levels of particulate matter <10-microm aerodynamic diameter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3). On cool days (<20 degrees C), all pollutants except O3 and SO2 were significantly associated with CVD admissions. For the two-pollutant models, CO, NO2, and O3 were significant in combination with each of the other four pollutants on warm days. On cool days, PM10 remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient pollutants increase the risk of hospital admissions for CVD.     

Long-term Exposure to PM2.5 and Incidence of Acute Myocardial Infarction

Background: A number of studies have shown associations between chronic exposure to particulate air pollution and increased mortality, particularly from cardiovascular disease, but fewer studies have examined the association between long-term exposure to fine particulate air pollution and specific cardiovascular events, such as acute myocardial infarction (AMI).Objective: We examined how long-term exposure to area particulate matter affects the onset of AMI, and we distinguished between area and local pollutants.Methods: Building on the Worcester Heart Attack Study, an ongoing community-wide investigation examining changes over time in myocardial infarction incidence in greater Worcester, Massachusetts, we conducted a case–control study of 4,467 confirmed cases of AMI diagnosed between 1995 and 2003 and 9,072 matched controls selected from Massachusetts resident lists. We used a prediction model based on satellite aerosol optical depth (AOD) measurements to generate both exposure to particulate matter ≤ 2.5 μm in diameter (PM_2.5) at the area level (10 × 10 km) and the local level (100 m) based on local land use variables. We then examined the association between area and local particulate pollution and occurrence of AMI.Results: An interquartile range (IQR) increase in area PM_2.5 (0.59 μg/m³) was associated with a 16% increase in the odds of AMI (95% CI: 1.04, 1.29). An IQR increase in total PM_2.5 (area + local, 1.05 μg/m³) was weakly associated with a 4% increase in the odds of AMI (95% CI: 0.96, 1.11).Conclusions: Residential exposure to PM_2.5 may best be represented by a combination of area and local PM_2.5, and it is important to consider spatial gradients within a single metropolitan area when examining the relationship between particulate matter exposure and cardiovascular events.     

Public Health and Air Pollution in Asia (PAPA): a multicity study of short-term effects of air pollution on mortality

Background and objectives

Although the deleterious effects of air pollution from fossil fuel combustion have been demonstrated in many Western nations, fewer studies have been conducted in Asia. The Public Health and Air Pollution in Asia (PAPA) project assessed the effects of short-term exposure to air pollution on daily mortality in Bangkok, Thailand, and in three cities in China: Hong Kong, Shanghai, and Wuhan.

Methods

Poisson regression models incorporating natural spline smoothing functions were used to adjust for seasonality and other time-varying covariates that might confound the association between air pollution and mortality. Effect estimates were determined for each city and then for the cities combined using a random effects method.

Results

In individual cities, associations were detected between most of the pollutants [nitrogen dioxide, sulfur dioxide, particulate matter ≤ 10 μm in aerodynamic diameter (PM₁₀), and ozone] and most health outcomes under study (i.e., all natural-cause, cardiovascular, and respiratory mortality). The city-combined effects of the four pollutants tended to be equal or greater than those identified in studies conducted in Western industrial nations. In addition, residents of Asian cities are likely to have higher exposures to air pollution than those in Western industrial nations because they spend more time outdoors and less time in air conditioning.

Conclusions

Although the social and environmental conditions may be quite different, it is reasonable to apply estimates derived from previous health effect of air pollution studies in the West to Asia.     

Systematic review and metaanalysis of air pollution exposure and risk of diabetes

The present systematic review and metaanalysis of published observational studies was conducted to assess the health effects of exposure to air pollution on diabetes risk. Online databases were searched through January 2013, and the reference lists of pertinent articles reporting observational studies in humans were examined. Pooled relative risks and 95 % confidence intervals were calculated with a random-effects model. Exposure to air pollution was associated with slight increase in risk of diabetes and susceptibility of people with diabetes to air pollution. These results were consistent between time-series, case-crossover and cohort studies and between studies conducted in North America and Europe. The association between exposure to air pollution and diabetes was stronger for gaseous pollutants than for particulate matter. Our metaanalysis suggests that exposure to air pollution may be a risk factor for diabetes and increase susceptibility of people with diabetes to air pollution.     

Air Pollution and Hospital Admissions for Ischemic Heart Diseases among Individuals 64+ Years of Age Residing in Seoul,Korea

There is increased evidence that air pollution may be associated with cardiovascular disease. The authors' prior investigations on the association between air pollution exposure and stroke mortality led to the current study, which was conducted to assess the effects of ambient air pollution on ischemic cardiovascular diseases among the elderly population (i.e., males and females 64+ yr of age) in Seoul, Korea. The authors estimated the relative risks of hospitalization associated with an interquartile range (IQR) increase in pollution concentrations; a generalized additive Poisson model was used to conduct a time-series analysis of the counts. The concentrations of ambient air pollutants were lower than the current recommendations for air quality in Korea. The estimated relative risks of hospitalization associated with an IQR were 1.05 (95% confidence interval [CI] = 1.01, 1.10) for particulate matter less than or equal to 10 pm in diameter (PM₁₀) (IQR = 40.4 μ/m³); 1.10 (95% CI = 1.05, 1.15) for ozone (IQR = 21.7 ppb); 1.08 (95% CI = 1.03, 1.14) for nitrogen dioxide (IQR = 14.6 ppb); 1.07 (95% CI = 1.01,1.13) for carbon monoxide (IQR = 1.0 ppm); and 0.95 (95% CI = 0.90, 1.01) for sulfur dioxide (IQR = 4.4 ppb). The authors observed that sulfur dioxide was a significant risk factor for ischemic heart disease-related hospital admissions during the summer months (i.e., June, July, and August) (relative risk = 1.32; 95% CI = 1.08, 1.62). Hospital admissions for ischemic heart diseases were associated significantly with daily variations in levels of ambient air pollutants. These findings may provide new insights into the possible pathologic mechanisms involving air pollutants, and they support the hypothesis that the elderly appear to be at particular risk from the effects of air pollution, at pollutant levels lower than the standards commonly adopted by many countries.     

Does particulate air pollution contribute to infant death? A systematic review

There is now substantial evidence that both short- and long-term increases in ambient air pollution are associated with increased mortality and morbidity in adults and children. Children's health is particularly vulnerable to environmental pollution, and infant mortality is still a major contributor to childhood mortality. In this systematic review we summarize and evaluate the current level of epidemiologic evidence of an association between particulate air pollution and infant mortality. We identified relevant publications using database searches with a comprehensive list of search terms and other established search methods. We included articles in the review according to specified inclusion criteria. Fifteen studies met our inclusion criteria. Evidence of an association between particulate air pollution and infant mortality in general was inconsistent, being reported from locations with largely comparable pollution levels. There was some evidence that the strength of association with particulate matter differed by subgroups of infant mortality. It was more consistent for postneonatal mortality due to respiratory causes and sudden infant death syndrome. Differential findings for various mortality subgroups within studies suggest a stronger association of particulate air pollution with some causes of infant death. Research is needed to confirm and clarify these links, using the most appropriate methodologies for exposure assessment and control of confounders.     

The burden of disease from indoor air pollution in developing countries: comparison of estimates

Four different methods have been applied to estimate the burden of disease due to indoor air pollution from household solid fuel use in developing countries (LDCs). The largest number of estimates involves applying exposure-response information from urban ambient air pollution studies to estimate indoor exposure concentrations of particulate air pollution. Another approach is to construct child survival curves using the results of large-scale household surveys, as has been done for India. A third approach involves cross-national analyses of child survival and household fuel use. The fourth method, referred to as the 'fuel-based' approach, which is explored in more depth here, involves applying relative risk estimates from epidemiological studies that use exposure surrogates, such as fuel type, to estimates of household solid fuel use to determine population attributable fractions by disease and age group. With this method and conservative assumptions about relative risks, 4-5 percent of the global LDC totals for both deaths and DALYs (disability adjusted life years) from acute respiratory infections, chronic obstructive pulmonary disease, tuberculosis, asthma, lung cancer, ischaemic heart disease, and blindness can be attributed to solid fuel use in developing countries. Acute respiratory infections in children under five years of age are the largest single category of deaths (64%) and DALYs (81%) from indoor air pollution, apparently being responsible globally for about 1.2 million premature deaths annually in the early 1990s.     

PM2.5暴露对儿童行为影响的系统综述

目的系统分析PM_2.5暴露对儿童行为的影响。方法以空气污染、细颗粒物、儿童、学生、儿童行为、神经行为、注意力、自闭症、孤独症谱系障碍、注意缺陷多动障碍、多动症、不良行为为中文关键词,以air pollution、fine particulate matter、particulate matter、PM2.5、children、student、behavior、autism、attention、inattention、neurobehavior、attention deficit hyperactivity disorder、ADHD、ASD为英文关键词,分别系统检索中国知网、万方数据知识服务平台和PubMed、Web of Science数据库发表的有关PM_2.5与儿童行为问题关联的相关文献。检索时段截至2019年11月,语种限定为中文和英文。纳入标准包括研究的暴露因素为PM2.5;研究结果包括行为障碍及相关疾病;纳入文献的语种为中文、英文;原创研究论文;病例对照、队列或横断面研究。排除标准包括动物实验;重复报告;综述类文章;研究暴露因素不包括PM_2.5;儿童自伤和违法等行为。最终纳入25篇文献。结果纳入的25篇文献中,12篇研究讨论PM_2.5暴露与儿童行为障碍疾病的关系,13篇探讨PM_2.5暴露与儿童异常行为之间的关系,基于中国人群的研究有5篇。根据研究设计分为出生队列研究(15个)、横断面研究(5个)、病例对照研究(5个),我国主要采用横断面研究和病例对照研究。研究结果提示,PM_2.5暴露会增加儿童行为问题的发生风险,既存在短期效应也存在长期效应。短期暴露于PM2.5易引起轻度的儿童异常行为,长期暴露可能加重儿童行为障碍疾病的发生风险。胎儿期和婴幼儿期可能是儿童行为问题发生的关键暴露窗口。结论PM_2.5暴露与儿童行为问题可能存在一定关联,在未来的研究中应开展纵向队列研究增强细颗粒物污染与儿童行为问题的因果关系论证。     

Lung Cancer and Cardiovascular Disease Mortality Associated with Ambient Air Pollution and Cigarette Smoke: Shape of the Exposure�CResponse Relationships

Background: Lung cancer and cardiovascular disease (CVD) mortality risks increase with smoking, secondhand smoke (SHS), and exposure to fine particulate matter < 2.5 μm in diameter (PM_2.5) from ambient air pollution. Recent research indicates that the exposure–response relationship for CVD is nonlinear, with a steep increase in risk at low exposures and flattening out at higher exposures. Comparable estimates of the exposure–response relationship for lung cancer are required for disease burden estimates and related public health policy assessments.Objectives: We compared exposure–response relationships of PM_2.5 with lung cancer and cardiovascular mortality and considered the implications of the observed differences for efforts to estimate the disease burden of PM_2.5.Methods: Prospective cohort data for 1.2 million adults were collected by the American Cancer Society as part of the Cancer Prevention Study II. We estimated relative risks (RRs) for increments of cigarette smoking, adjusting for various individual risk factors. RRs were plotted against estimated daily dose of PM_2.5 from smoking along with comparison estimates for ambient air pollution and SHS.Results: For lung cancer mortality, excess risk rose nearly linearly, reaching maximum RRs > 40 among long-term heavy smokers. Excess risks for CVD mortality increased steeply at low exposure levels and leveled off at higher exposures, reaching RRs of approximately 2–3 for cigarette smoking.Conclusions: The exposure–response relationship associated with PM_2.5 is qualitatively different for lung cancer versus cardiovascular mortality. At low exposure levels, cardiovascular deaths are projected to account for most of the burden of disease, whereas at high levels of PM_2.5, lung cancer becomes proportionately more important.     

Integrated assessment of exposure to PM2.5 in South India and its relation with cardiovascular risk: Design of the CHAI observational cohort study

While there is convincing evidence that fine particulate matter causes cardiovascular mortality and morbidity, little of the evidence is based on populations outside of high income countries, leaving large uncertainties at high exposures. India is an attractive setting for investigating the cardiovascular risk of particles across a wide concentration range, including concentrations for which there is the largest uncertainty in the exposure-response relationship.CHAI is a European Research Council funded project that investigates the relationship between particulate air pollution from outdoor and household sources with markers of atherosclerosis, an important cardiovascular pathology. The project aims to (1) characterize the exposure of a cohort of adults to particulate air pollution from household and outdoor sources (2) integrate information from GPS, wearable cameras, and continuous measurements of personal exposure to particles to understand where and through which activities people are most exposed and (3) quantify the association between particles and markers of atherosclerosis. CHAI has the potential to make important methodological contributions to modeling air pollution exposure integrating outdoor and household sources as well as in the application of wearable camera data in environmental exposure assessment.     

住宅室内空气颗粒物污染状况及其与大气浓度关系的初探

目的了解当前住宅室内空气PM2.5和PM10的污染水平及其与室外大气浓度的关系。方法选择10户市区常住家庭,采用单孔多段冲击式颗粒物采样仪进行室内外空气PM2.5、PM10浓度的同时监测。结果非采暖期室内空气PM2.5和PM10的浓度范围分别为27.0～272.9μgm3和42.9～309.6μgm3;采暖期分别为20.7～251.4μgm3和34.0～283.9μgm3。PM2.5与PM10浓度之间呈良好的直线相关关系。室内外颗粒物浓度的相关关系在非采暖期和采暖期有所不同。结论住宅室内空气颗粒物污染比较严重,今后应进一步研究室内颗粒物的污染规律,探讨颗粒物对人群健康的影响。     

Influences of study design and location on the relationship between particulate matter air pollution and birthweight

A large number of studies have identified a relationship between particulate matter air pollution and birthweight. Although reported associations are small and varied, they have been identified in studies from places around the world. Exposure assignment, covariates and study inclusion criteria vary among studies. To examine the effect of these and other study characteristics on associations between particulate matter and birthweight, US birth records for singletons delivered at 40 weeks gestation in 2001-03 during the months of March, June, September and December were linked to quarterly estimates of pollution exposure, both particulate matter exposure and exposure to multiple pollutants, by county of residence and month of birth. Annual, 9-month and trimester-specific exposures were assigned. Among births linked to particulate matter exposure there was a small association between coarse particle exposure and birthweight (beta -13 g per 10 microg/m(3) increase [95% CI -18.3 g, -7.6 g]) after controlling for maternal factors; this association was attenuated slightly and remained statistically significant after further adjustment for contextual factors, year of birth, region, or urban-rural status. The associations were slightly weaker among births linked to multiple pollutant exposure than among births linked to just particulate matter exposure. The association varied markedly by region, ranging from a decrement of 43 g per 10 microg/m(3)[95% CI -58.6 g, -27.6 g] in the north-west to a null association in the south-west. Trimester findings were smaller, yet remained significant and varied regionally. The association between fine particle exposure and birthweight varied considerably, with an overall small positive association that became null after control for region. This study found that wide regional differences in association may contribute to the varied published findings. The association between coarse particle exposure and birthweight appeared robust, if small; fine particles had no overall association with birthweight.     

The Public Health and Air Pollution in Asia (PAPA) Project: estimating the mortality effects of particulate matter in Bangkok, Thailand

BACKGROUND: Air pollution data in Bangkok, Thailand, indicate that levels of particulate matter with aerodynamic diameter < or = 10 microm (PM(10)) are significantly higher than in most cities in North America and Western Europe, where the health effects of PM(10) are well documented. However, the pollution mix, seasonality, and demographics are different from those in developed Western countries. It is important, therefore, to determine whether the large metropolitan area of Bangkok is subject to similar effects of PM(10). OBJECTIVES: This study was designed to investigate the mortality risk from air pollution in Bangkok, Thailand. METHODS: The study period extended from 1999 to 2003, for which the Ministry of Public Health provided the mortality data. Measures of air pollution were derived from air monitoring stations, and information on temperature and relative humidity was obtained from the weather station in central Bangkok. The statistical analysis followed the common protocol for the multicity PAPA (Public Health and Air Pollution Project in Asia) project in using a natural cubic spline model with smooths of time and weather. RESULTS: The excess risk for non-accidental mortality was 1.3% [95% confidence interval (CI), 0.8-1.7] per 10 microg/m(3) of PM(10), with higher excess risks for cardiovascular and above age 65 mortality of 1.9% (95% CI, 0.8-3.0) and 1.5% (95% CI, 0.9-2.1), respectively. In addition, the effects from PM(10) appear to be consistent in multipollutant models. CONCLUSIONS: The results suggest strong associations between several different mortality outcomes and PM(10). In many cases, the effect estimates were higher than those typically reported in Western industrialized nations.     

Ambient air pollution exposure and damage to male gametes: human studies and in situ ‘sentinel’ animal experiments

Globally there is concern that adverse reproductive outcomes and fertility impairment in humans may be caused by exposure to environmental contaminants. Air pollution in particular has been linked to DNA damage, abnormal sperm morphology, and reduced sperm performance in men. Experimental studies using model species (mice and rats) exposed in situ provide evidence that ambient air pollution can cause damage to the respiratory system and other tissues or organs. This can take the form of DNA damage and other genetic changes throughout the body, including induced mutations, DNA strand breaks, and altered methylation patterns in male germ cells. Human and animal studies together provide strong evidence that air pollution, especially airborne particulate matter, at commonly occurring ambient levels is genotoxic to male germ cells. The mechanistic link between air pollution exposure and induced genetic changes in male germ cells is currently unclear. ‘Sentinel’ animal experiments explicitly examining air pollution affects on sperm quality in laboratory rodents have not been conducted and would provide a critical link to observations in humans. The importance of air pollution compared to other factors affecting fertility and reproductive outcomes in humans is not clear and warrants further investigation.     

Ambient particulate air pollution and circulating C-reactive protein level: A systematic review and meta-analysis

BackgroundAmbient particulate air pollution is a major threat to the cardiovascular health of people. Inflammation is an important component of the pathophysiological process that links air pollution and cardiovascular disease (CVD). A classical marker of inflammation—C-reactive protein (CRP), has been recognized as an independent predictor of CVD risk. Exposure to ambient particulate matter (PM) may cause systemic inflammatory response but its association with CRP has been inconsistently reported.ObjectivesTo estimate the potential effects of short-term and long-term exposures to ambient particulate air pollution on circulating CRP level based on previous epidemiological studies.MethodsA systematic literature search of PubMed, Web of Science, Embase, and Scopus databases for publications up to January 2018 was conducted for studies reporting the association between ambient PM (PM_2.5 or PM₁₀, or both) and circulating CRP level. We performed a meta-analysis for the associations reported in individual studies using a random-effect model and evaluated the effect modification by major potential modifiers.ResultsThis meta-analysis comprised data from 40 observational studies conducted on 244,681 participants. These included 32 (27 PM_2.5 studies and 13 PM₁₀ studies) and 11 (9 PM_2.5 studies and 5 PM₁₀ studies) studies that investigated the associations of CRP with short-term and long-term exposure to particulate air pollution, respectively. A 10 μg/m³ increase in short-term exposure to PM_2.5 and PM₁₀ was associated with increases of 0.83 % (95% CI: 0.30%, 1.37%) and 0.39% (95% CI: -0.04%, 0.82%) in CRP level, respectively, and a 10 μg/m³ increase in long-term exposure to PM_2.5 and PM₁₀ was associated with much higher increases of 18.01% (95% CI: 5.96%, 30.06%) and 5.61% (95% CI: 0.79%, 10.44%) in CRP level, respectively. The long-term exposure to particulate air pollution was more strongly associated with CRP level than short-term exposure and PM_2.5 had a greater effect on CRP level than PM₁₀.ConclusionExposure to ambient particulate air pollution is associated with elevated circulating CRP level suggesting an activated systemic inflammatory state upon exposure, which may explain the association between particulate air pollution and CVD risk.     

Air pollution and population health: a global challenge

“Air pollution and population health” is one of the most important environmental and public health issues. Economic development, urbanization, energy consumption, transportation/motorization, and rapid population growth are major driving forces of air pollution in large cities, especially in megacities. Air pollution levels in developed countries have been decreasing dramatically in recent decades. However, in developing countries and in countries in transition, air pollution levels are still at relatively high levels, though the levels have been gradually decreasing or have remained stable during rapid economic development. In recent years, several hundred epidemiological studies have emerged showing adverse health effects associated with short-term and long-term exposure to air pollutants. Time-series studies conducted in Asian cities also showed similar health effects on mortality associated with exposure to particulate matter (PM), sulfur dioxide (SO₂), nitrogen dioxide (NO₂) and ozone (O₃) to those explored in Europe and North America. The World Health Organization (WHO) published the “WHO Air Quality Guidelines (AQGs), Global Update” in 2006. These updated AQGs provide much stricter guidelines for PM, NO₂, SO₂ and O₃. Considering that current air pollution levels are much higher than the WHO-recommended AQGs, interim targets for these four air pollutants are also recommended for member states, especially for developing countries in setting their country-specific air quality standards. In conclusion, ambient air pollution is a health hazard. It is more important in Asian developing countries within the context of pollution level and population density. Improving air quality has substantial, measurable and important public health benefits.