Social disadvantage, air pollution, and asthma physician visits in Toronto, Canada

Background

Previous research demonstrates that ambient air pollution exacerbates asthma. Asthma morbidity also varies with socioeconomic position (SEP). Few studies have examined if ambient air pollution has a differential impact on income subgroups of the population. This paper investigates socioeconomic variation in ambulatory physician consultations for asthma and assesses possible effect modification of SEP on the association between physician visits and air pollution for children aged 1-17 and adults aged 18-64 in Toronto, Canada, between 1992 and 2001.

Methods

Generalized additive models and generalized linear models were used to estimate the adjusted risk of asthma physician visits associated with an interquartile range increase in sulfur dioxide (SO₂), nitrogen dioxide (NO₂), particulate matter (PM_2.5), and ozone (O₃).

Results

A socioeconomic gradient in the number of physician visits was observed among children and adults and both sexes. SO₂, NO₂, and PM_2.5 had positive associations with physician visits. The risk ratios for the low socioeconomic group were significantly greater than those for the high socioeconomic group in several of the models of SO₂ and PM_2.5.

Conclusions

These findings suggest increased ambulatory physician visits represent another component of the public health impact of urban air pollution. The burden of this impact may be borne disproportionately by those with lower SEP. Clarifying the role of SEP in altering susceptibility to the effects of air pollution is essential not only to inform revisions of ambient air quality standards, but also to design public health interventions to reduce health impacts on sensitive subgroups of the population.     

Effects of air pollution on exhaled nitric oxide in children: Results from the GINIplus and LISAplus studies

Most previous studies which have investigated the short-term effects of air pollution on airway inflammation, assessed by an increase of exhaled nitric oxide (eNO), have been conducted among asthmatic children. Few studies have considered this potential association among non-asthmatics. Furthermore, although both short- and long-term effects of air pollution on eNO had been reported separately, studies which include both are scarce. We explored associations between 24 h NO₂ and PM₁₀ (particles with aerodynamic diameters below 10 μm) mass with eNO in 1985 children (192 asthmatics and 1793 non-asthmatics) aged 10 years and accounted for the long-term effects of air pollution by adjusting for annual averages of NO₂, PM₁₀ mass, PM_2.5 mass (particles with aerodynamic diameters below 2.5 μm) and PM_2.5 absorbance, using data from two German birth cohorts in Munich and Wesel. In total, robust associations between 24 h NO₂ and eNO were observed in both single-pollutant (percentage change: 18.30%, 95% confidence interval: 11.63–25.37) and two-pollutant models (14.62%, 6.71–23.11). The association between 24 h PM₁₀ mass and eNO was only significant in the single-pollutant model (9.59%, 4.80–14.61). The same significant associations were also observed in non-asthmatic children, while they did not reach significant levels in asthmatic children. Associations between annual averages of ambient air pollution (NO₂, PM₁₀ mass, PM_2.5 mass and PM_2.5 absorbance) and eNO were consistently null. In conclusion, significantly positive associations were observed between short-term ambient air pollution and eNO. No long-term effects of air pollution on eNO were found in this study.     

An assessment of air pollution and its attributable mortality in Ulaanbaatar, Mongolia

Epidemiologic studies have consistently reported associations between outdoor fine particulate matter (PM_2.5) air pollution and adverse health effects. Although Asia bears the majority of the public health burden from air pollution, few epidemiologic studies have been conducted outside of North America and Europe due in part to challenges in population exposure assessment. We assessed the feasibility of two current exposure assessment techniques, land use regression (LUR) modeling and mobile monitoring, and estimated the mortality attributable to air pollution in Ulaanbaatar, Mongolia. We developed LUR models for predicting wintertime spatial patterns of NO₂ and SO₂ based on 2-week passive Ogawa measurements at 37 locations and freely available geographic predictors. The models explained 74% and 78% of the variance in NO₂ and SO₂, respectively. Land cover characteristics derived from satellite images were useful predictors of both pollutants. Mobile PM_2.5 monitoring with an integrating nephelometer also showed promise, capturing substantial spatial variation in PM_2.5 concentrations. The spatial patterns in SO₂ and PM, seasonal and diurnal patterns in PM_2.5, and high wintertime PM_2.5/PM₁₀ ratios were consistent with a major impact from coal and wood combustion in the city’s low-income traditional housing (ger) areas. The annual average concentration of PM_2.5 measured at a centrally located government monitoring site was 75 μg/m³ or more than seven times the World Health Organization’s PM_2.5 air quality guideline, driven by a wintertime average concentration of 148 μg/m³. PM_2.5 concentrations measured in a traditional housing area were higher, with a wintertime mean PM_2.5 concentration of 250 μg/m³. We conservatively estimated that 29% (95% CI, 12–43%) of cardiopulmonary deaths and 40% (95% CI, 17–56%) of lung cancer deaths in the city are attributable to outdoor air pollution. These deaths correspond to nearly 10% of the city’s total mortality, with estimates ranging to more than 13% of mortality under less conservative model assumptions. LUR models and mobile monitoring can be successfully implemented in developing country cities, thus cost-effectively improving exposure assessment for epidemiology and risk assessment. Air pollution represents a major threat to public health in Ulaanbaatar, Mongolia, and reducing home heating emissions in traditional housing areas should be the primary focus of air pollution control efforts.     

Does exposure to air pollution in urban parks have socioeconomic, racial or ethnic gradients?

Little is known about the levels of air pollution at public parks where regular exercise takes place or in park-adjacent neighborhoods where people have easy access to parks. In this study we investigated the ambient concentrations of criteria pollutants nitrogen dioxide (NO₂), fine particulate (PM_2.5) and ozone (O₃) at public parks and in park-adjacent neighborhoods for metropolitan Los Angeles. Socioeconomic and racial-ethnic inequalities in exposure to the three criteria pollutants were also investigated using multiple linear regression models. In addition, differences in inhalation doses from breathing the three +criteria pollutants were investigated for the top and bottom quartile racial composition in the parks and neighborhoods. Our research showed that although public parks had on average the lowest pollutant concentrations of NO₂ and PM_2.5, they had relatively high O₃ concentrations. Park-adjacent neighborhoods, by contrast, had the highest NO₂ and PM_2.5 concentrations, but the lowest O₃ concentrations. Higher exposures to NO₂ and PM_2.5 were systematically identified for the lower socioeconomic position or higher minority population neighborhoods. For children and adolescents aged 6–15 engaging in high and moderate intensity activities in and around public parks, those from the top quartile of primarily Hispanic neighborhoods had much higher (63%) inhaled doses of NO₂ compared to the bottom quartile counterpart. PM_2.5 showed a similar but less pronounced pattern of inhalation doses. Evidence of socioeconomic and racial-ethnic gradients was found in air pollution exposure and inhalation doses in and around the urban parks in Los Angeles. This suggests that patterns of exposure inequality found in other environmental justice research are present in exposures in and around urban parks.     

Does attainment status for the PM10 National Air Ambient Quality Standard change the trend in ambient levels of particulate matter?

Despite increasingly stringent and cost-demanding national, state, and local air quality regulations, adverse health effects associated with ambient exposure to air pollution persist. Accountability research, aimed at evaluating the effects of air quality regulation on health outcome, is increasingly viewed as an essential component of responsible government intervention. In this paper, we focused on assessing the impact of air quality regulations on ambient levels of air pollution. We considered two groups of counties: the first group (A) includes counties that in 1991 were designated as in attainment or unclassifiable with respect to the 1987 National Ambient Air Quality Standards (NAAQS) and maintained their status through 2006; the second group (Ā), includes counties that in 1991 were designated as nonattainment and were subsequently redesignated as in attainment. We hypothesized that if air pollution control programs adopted to meet the NAAQS are effective in reducing air pollution levels, counties in group Ā will experience a sharper decrease in PM₁₀ levels than counties in group A. To provide evidence to support this hypothesis, Bayesian hierarchical models were developed for estimating 1) the yearly percentage change in ambient PM₁₀ levels for 100 counties and the entire USA during the period 1987–2007 and 2) the change in PM₁₀ ambient levels in counties in group Ā compared with counties in group A. We found statistically significant evidence of variability across counties in trends of PM₁₀ concentrations. We also found strong evidence that counties transitioning from nonattainment to attainment status during the period 1987–2007 experienced a sharper decline in PM₁₀ when compared with counties that were always in attainment.     

Acute effects of urban and industrial pollution in a government-designated “Environmental risk area”: the case of Brindisi,Italy

Exposure to air pollutants has been associated with increased hospital admissions (HAs) for respiratory and cardiovascular diseases. This work describes a short-term epidemiological study in Brindisi, a highly industrialized town in Southern Italy. The effects of daily exposure to PM₁₀ and NO₂ on daily HAs for cardiac, respiratory, and cerebrovascular diseases were investigated by means of a case-crossover design in the period 2001–2007. Results showed positive associations between PM₁₀ and HAs for cardiac and respiratory diseases and between NO₂ and HAs for all the categories of diseases considered, particularly among females. Although not statistically significant, increased risk was observed for wind blowing from the port and the industrial area. Findings confirm the health risks associated with ambient air pollution exposure, even though NO₂ and PM₁₀ concentrations were below the legal limits. This may be due to the complex scenario of emissions in the area, which should be better investigated.     

Effects of ambient air pollution on pulmonary function among schoolchildren

Literature has shown adverse effects of ambient air pollution exposure on various asthma related outcomes in childhood. However, the associated evidence on pulmonary function effects is still inconsistent.We conducted a population-based study comprised of seventh-grade children in 14 Taiwanese communities. Pulmonary function tests and questionnaires were completed on 3957 subjects. We evaluated the effects of ambient air pollution exposures based on the data collected in 2005–2007 by existing air monitoring stations. Multiple linear mixed effect models were fitted to estimate the relationship between community pollutant levels and pulmonary function indices. After adjustment for individual-level confounders, pulmonary function differed only slightly between communities with different levels of air pollution. We found greater effects of ambient air pollutants on pulmonary function for boys than for girls. Among boys, traffic-related pollutants CO, NOx, NO₂, and NO were generally associated with chronic adverse effects on FVC and FEV₁, and subchronic adverse effects mainly on maximal mid-expiratory flow (MMEF) and peak expiratory flow rate. Among girls, only NOx and NO₂ showed subchronic adverse effects on MMEF. Although effect estimates of SO₂, PM₁₀, and PM_2.5 were generally negative for boys, none achieved statistical significance.Our data suggests that ambient traffic-related pollution had chronic adverse effects on pulmonary function in schoolchildren, especially for boys.     

Impact of air pollution on educational attainment for respiratory health treated students: A cross sectional data linkage study

IntroductionThere is some evidence that exam results are worse when students are acutely exposed to air pollution. Studies investigating the association between air pollution and academic attainment have been constrained by small sample sizes.MethodsCross sectional educational attainment data (2009–2015) from students aged 15–16 years in Cardiff, Wales were linked to primary health care data, modelled air pollution and measured pollen data, and analysed using multilevel linear regression models. Annual cohort, school and individual level confounders were adjusted for in single and multi-pollutant/pollen models. We stratified by treatment of asthma and/or Seasonal Allergic Rhinitis (SAR).ResultsA unit (10μg/m³) increase of short-term exposure to NO₂ was associated with 0.044 (95% CI: −0.079, −0.008) reduction of standardised Capped Point Score (CPS) after adjusting for individual and household risk factors for 18,241 students. This association remained statistically significant after controlling for other pollutants and pollen. There was no association of PM_2.5, O₃, or Pollen with standardised CPS remaining after adjustment. We found no evidence that treatment for asthma or SAR modified the observed NO₂ effect on educational attainment.ConclusionOur study showed that short-term exposure to traffic-related air pollution, specifically NO_2, was associated with detrimental educational attainment for students aged 15–16. Longitudinal investigations in different settings are required to confirm this possible impact and further work may uncover the long-term economic implications, and degree to which impacts are cumulative and permanent.     

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.     

Estimated acute effects of ambient ozone and nitrogen dioxide on mortality in the Pearl River Delta of southern China

Background and objectives: Epidemiologic studies have attributed adverse health effects to air pollution; however, controversy remains regarding the relationship between ambient oxidants [ozone (O₃) and nitrogen dioxide (NO₂)] and mortality, especially in Asia. We conducted a four-city time-series study to investigate acute effects of O₃ and NO₂ in the Pearl River Delta (PRD) of southern China, using data from 2006 through 2008.Methods: We used generalized linear models with Poisson regression incorporating natural spline functions to analyze acute mortality in association with O₃ and NO₂, with PM₁₀ (particulate matter ≤ 10 μm in diameter) included as a major confounder. Effect estimates were determined for individual cities and for the four cities as a whole. We stratified the analysis according to high- and low- exposure periods for O₃.Results: We found consistent positive associations between ambient oxidants and daily mortality across the PRD cities. Overall, 10-μg/m³ increases in average O₃ and NO₂ concentrations over the previous 2 days were associated with 0.81% [95% confidence interval (CI): 0.63%, 1.00%] and 1.95% (95% CI: 1.62%, 2.29%) increases in total mortality, respectively, with stronger estimated effects for cardiovascular and respiratory mortality. After adjusting for PM₁₀, estimated effects of O₃ on total and cardiovascular mortality were stronger for exposure during high-exposure months (September through November), whereas respiratory mortality was associated with O₃ exposure during nonpeak exposure months only.Conclusions: Our findings suggest significant acute mortality effects of O₃ and NO₂ in the PRD and strengthen the rationale for further limiting the ambient pollution levels in the area.     

The effects of air pollution on length of hospital stay for adult patients with asthma

Length of hospital stay (LOS) of asthma can be a reflection of the disease burden faced by patients, and it is also sensitive to air pollution. This study aims at estimating and validating the effects of air pollution and readmission on the LOS for those who have asthma, considering their readmission history, minimum temperature, and threshold effects of air pollutants. In addition, sex, age, and season were also constructed for stratification to achieve more precise and specific results. The results show that no significant effects of PM_2.5 and NO₂ on LOS were observed in any of the patients, but there were significant effects of PM_2.5 and NO₂ on LOS when a stratifying subgroup analysis was performed. The effect of PM₁₀ on LOS was found to be lower than that of PM_2.5 and higher than that of NO₂. SO₂ did not have a significant effect on LOS for patients with asthma in our study. Our study confirmed that the adverse effects of air pollutants (such as PM₁₀) on LOS for patients with asthma existed; in addition, these effects vary for different stratifications. We measured the effects of air pollutants on the LOS for patients with asthma, and this study offers policy makers quantitative evidence that can support relevant policies for health care resource management and ambient air pollutants control.     

Influence of socioeconomic conditions on air pollution adverse health effects in elderly people: an analysis of six regions in São Paulo, Brazil

Study objective: To evaluate if the effects of particulate matter (PM₁₀) on respiratory mortality of elderly people are affected by socioeconomic status. Design: Time series studies. The daily number of elderly respiratory deaths were modelled in generalised linear Poisson regression models controlling for long term trend, weather, and day of the week, from January 1997 to December 1999, in six different regions of São Paulo City, Brazil. The regions were defined according to the proximity of air pollution monitoring stations. Three socioeconomic indicators were used: college education, monthly income, and housing. Main results: For a 10 µg/m³ increase in PM₁₀, the percentage increase in respiratory mortality varied from 1.4% (95% CI 5.9 to 8.7) to 14.2% (95% CI 0.4 to 28.0). The overall percentage increase in the six regions was 5.4% (95% CI 2.3 to 8.6). The effect of PM₁₀ was negatively correlated with both percentage of people with college education and high family income, and it was positively associated with the percentage of people living in slums. Conclusions: These results suggest that socioeconomic deprivation represents an effect modifier of the association between air pollution and respiratory deaths.     

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.     

The public health context for PM2.5 and ozone air quality trends

Tropospheric ozone (O₃) and particulate matter (PM_2.5) are associated with adverse health effects, including premature mortality. Regulation of these pollutants by the US Environmental Protection Agency has resulted in significant improvements in air quality over the last decade, as demonstrated by a national network of air quality monitors. However, ambient trends provide limited information regarding either the change in population exposure to these pollutants or how fluctuations in the levels of these pollutants might affect public health. We leverage the spatially and temporally extensive monitoring network in the US to estimate the improvements to public health associated with monitored air quality changes over a 7-year period. We estimate the impacts of monitored changes in ozone and PM_2.5 on premature mortality using health impact functions based on short-term relative risk estimates for O₃ and long-term relative risk estimates for PM_2.5. We spatially interpolate the O₃ and PM_2.5 data and utilize ozone air quality data that are adjusted for meteorological variability. We estimate that reductions in monitored PM_2.5 and ozone from 2000 to 2007 are associated with 22,000–60,000 PM_2.5 and 880–4,100 ozone net avoided premature mortalities. The change in estimated premature mortality can be highly variable from 1 year to the next, sometimes by thousands of deaths. The estimate of avoided ozone-related mortalities is sensitive to the use of meteorologically-adjusted air quality inputs. Certain locations, including Los Angeles and Houston see an opposing trend between mortality impacts attributable to ozone and PM_2.5.We find that improving air quality over the past 7 years has reduced premature mortality significantly.     

Associations between ambient air pollution and bone turnover markers in 10-year old children: Results from the GINIplus and LISAplus studies

Negative associations between bone turnover markers and bone mineral density have been reported. In order to study the association between ambient air pollution and bone turnover markers, as indicators of bone loss, we investigated associations between land-use regression modeled air pollution (NO₂, PM_2.5 mass, PM_{2.5 – 10} [coarse particles], PM₁₀ mass and PM_2.5 absorbance) and bone turnover markers in 2264 children aged 10 years. Serum osteocalcin and C-terminal telopeptide of type I collagen (CTx), measured by Modular-System (Roche), were the two bone turnover markers considered in this analysis. In total population, NO₂, PM_{2.5 – 10} and PM₁₀ mass exposure were positively and significantly associated with both osteocalcin and CTx. A 2.5 (95% CI: 0.6, 4.4) ng/ml increase in osteocalcin and a 24.0 (95% CI: 6.7, 41.3) ng/L increase in CTx were observed per IQR (6.7 μg/m³) increase in NO₂, independent of socioeconomic status, sex, age, pubertal status, fasting status and total physical activity. The estimated coefficients were 3.0 (95% CI: 0.1, 5.8) for osteocalcin and 32.3 (95% CI: 6.1, 58.5) for CTx with PM_{2.5 – 10}; 3.2 (95% CI: 0.0, 6.4) for osteocalcin and 30.7 (95% CI: 1.7, 59.7) for CTx with PM₁₀. Children living close to a major road (≤ 350 m) had higher levels of both osteocalcin (1.4 [−1.2, 4.0] ng/ml) and CTx (16.2 [−7.4, 39.8] ng/L). The adverse impact of ambient air pollution on bone turnover rates observed in one of the study areas showed stimulation of more such studies.     

Extreme ambient temperatures and cardiorespiratory emergency room visits: assessing risk by comorbid health conditions in a time series study

Background

Both air pollution exposure and socioeconomic status (SES) are important indicators of children’s health. Using highly resolved modeled predictive surfaces, we examine the joint effects of air pollution exposure and measures of SES in a population level analysis of pregnancy outcomes in North Carolina (NC).

Methods

Daily measurements of particulate matter <2.5 μm in aerodynamic diameter (PM_2.5) and ozone (O₃) were calculated through a spatial hierarchical Bayesian model which produces census-tract level point predictions. Using multilevel models and NC birth data from 2002–2006, we examine the association between pregnancy averaged PM_2.5 and O₃, individual and area-based SES indicators, and birth outcomes.

Results

Maternal race and education, and neighborhood household income were associated with adverse birth outcomes. Predicted concentrations of PM_2.5 and O₃ were also associated with an additional effect on reductions in birth weight and increased risks of being born low birth weight and small for gestational age.

Conclusions

This paper builds on and complements previous work on the relationship between pregnancy outcomes and air pollution exposure by using 1) highly resolved air pollution exposure data; 2) a five-year population level sample of pregnancies; and 3) including personal and areal level measures of social determinants of pregnancy outcomes. Results show a stable and negative association between air pollution exposure and adverse birth outcomes. Additionally, the more socially disadvantaged populations are at a greater risk; controlling for both SES and environmental stressors provides a better understanding of the contributing factors to poor children’s health outcomes.     

Air pollution and admissions for acute lower respiratory infections in young children of Ho Chi Minh City

This study assessed the effects of exposure to air pollution on hospitalization for acute lower respiratory infection (ALRI) among children under 5 years of age in Ho Chi Minh City (HCMC) from 2003 to 2005. Case-crossover analyses with time-stratified selection of control periods were conducted using daily admissions for pneumonia and bronchiolitis and daily, citywide averages of PM₁₀, NO₂, SO₂, and O₃ (8-h maximum average) estimated from the local air quality monitoring network. Increased concentrations of NO₂ and SO₂ were associated with increased admissions in the dry season (November to April), with excess risks of 8.50% (95%CI 0.80–16.79) and 5.85% (95%CI 0.44–11.55), respectively. PM₁₀ could also be associated with increased admissions in the dry season, but high correlation between PM₁₀ and NO₂ (0.78) limits our ability to distinguish between PM₁₀ and NO₂ effects. In the rainy season (May–October), negative associations between pollutants and admissions were observed. Results of this first study of the health effects of air pollution in HCMC support the presence of an association between combustion-source pollution and increased ALRI admissions. ALRI admissions were generally positively associated with ambient levels of PM₁₀, NO₂, and SO₂ during the dry season, but not the rainy season. Negative results in the rainy season could be driven by residual confounding present from May to October. Preliminary exploratory analyses suggested that seasonal differences in the prevalence of viral causes of ALRI could be driving the observed differences in effects by season.     

Ambient Air Pollution and Daily Outpatient Visits for Cardiac Arrhythmia in Shanghai,China

Background

Cardiac arrhythmias are cardiac rhythm disorders that comprise an important public health problem. Few prior studies have examined the association between ambient air pollution and arrhythmias in general populations in mainland China.

Methods

We performed a time-series analysis to investigate the short-term association between air pollution (particulate matter with an aerodynamic diameter less than 10 µm [PM₁₀], sulfur dioxide [SO₂], and nitrogen dioxide [NO₂]) and outpatient visits for arrhythmia in Shanghai, China. We applied the over-dispersed Poisson generalized additive model to analyze the associations after control for seasonality, day of the week, and weather conditions. We then stratified the analyses by age, gender, and season.

Results

We identified a total of 56 940 outpatient visits for cardiac arrhythmia. A 10-µg/m³ increase in the present-day concentrations of PM₁₀, SO₂, and NO₂ corresponded to increases of 0.56% (95% CI 0.42%, 0.70%), 2.07% (95% CI 1.49%, 2.64%), and 2.90% (95% CI 2.53%, 3.27%), respectively, in outpatient arrhythmia visits. The associations were stronger in older people (aged ≥65 years) and in females. This study provides the first evidence that ambient air pollution is significantly associated with increased risk of cardiac arrhythmia in mainland China.

Conclusions

Our analyses provide evidence that the current air pollution levels have an adverse effect on cardiovascular health and strengthened the rationale for further limiting air pollution levels in the city.Key words: air pollution, outpatient visits, cardiac arrhythmias, time-series     

Short-Term Effects of Nitrogen Dioxide on Mortality and Susceptibility Factors in 10 Italian Cities: The EpiAir Study

Background: Several studies have shown an association between nitrogen dioxide (NO₂) and mortality. In Italy, the EpiAir multicentric study, “Air Pollution and Health: Epidemiological Surveillance and Primary Prevention,” investigated short-term health effects of air pollution, including NO₂.Objectives: To study the individual susceptibility, we evaluated the association between NO₂ and cause-specific mortality, investigating individual sociodemographic features and chronic/acute medical conditions as potential effect modifiers.Methods: We considered 276,205 natural deaths of persons > 35 years of age, resident in 10 Italian cities, and deceased between 2001 and 2005. We chose a time-stratified case-crossover analysis to evaluate the short-term effects of NO₂ on natural, cardiac, cerebrovascular, and respiratory mortality. For each subject, we collected information on sociodemographic features and hospital admissions in the previous 2 years. Fixed monitors provided daily concentrations of NO₂, particulate matter ≤ 10 μm in aerodynamic diameter (PM₁₀) and ozone (O₃).Results: We found statistically significant associations with a 10-μg/m³ increase of NO₂ for natural mortality [2.09% for lag 0–5; 95% confidence interval (CI), 0.96–3.24], for cardiac mortality (2.63% for lag 0–5; 95% CI, 1.53–3.75), and for respiratory mortality (3.48% for lag 1–5; 95% CI, 0.75–6.29). These associations were independent from those of PM₁₀ and O₃. Stronger associations were estimated for subjects with at least one hospital admission in the 2 previous years and for subjects with three or more specific chronic conditions. Some cardiovascular conditions (i.e., ischemic heart disease, pulmonary circulation impairment, heart conduction disorders, heart failure) and diabetes appeared to confer a strong susceptibility to air pollution.Conclusions: Our results suggest significant and likely independent effects of NO₂ on natural, cardiac, and respiratory mortality, particularly among subjects with specific cardiovascular preexisting chronic conditions and diabetes.     

Is particulate air pollution associated with health and health inequalities in New Zealand?

Air pollution can increase mortality risk and may also exacerbate socioeconomic inequalities in health outcomes. This New Zealand study investigated whether exposure to particulate air pollution (PM₁₀) was associated with mortality and health inequalities. Annual mean PM₁₀ estimates for urban Census Area Units (CAUs) were linked to cause-specific mortality data. A dose-response relationship was found between PM₁₀ and respiratory disease mortality, including at concentrations below the existing annual average guideline value of 20 μg m⁻³. Establishing and enforcing a lower guideline value is likely to have population health benefits. However, socioeconomic inequalities in respiratory disease mortality were not significantly elevated with PM₁₀ exposure.