Short-term effect of PM2.5 on daily hospital admissions in Madrid (2003–2005)

The aim of this paper was to analyse the effect of particulate matter PM_2.5, a recent air quality guideline value for the protection of health, on hospital admissions in Madrid, Spain. This dependent variable was used as a measure against the daily number of emergency hospital admissions from 2003–2005. The causes analysed were: all causes, respiratory and circulatory. The independent variables were daily records of PM_2.5, PM₁₀, NO₂, NO_x, SO₂ and O₃. Seasonalities, trend, flu epidemics, noise and pollen were used as control variables. Poisson Regression Models were performed to calculate the Relative Risk (RR) and the Attributable Risk (AR). The function relationship with hospital admissions was linear and without threshold. The RR for an increase of 25 μg/m³ in PM_2.5 concentrations was 1.07 IC 95% (1.05 1.09) for all causes; for circulatory was 1.08 IC 95%: (1.03 1.13) and for respiratory was 1.07 IC 95% (1.02 1.11). PM_2.5 concentrations were the only primary pollutant that showed a statistical association with hospital admissions in Madrid.     

Reduction of wheat photosynthesis by fine particulate (PM2.5) pollution over the North China Plain

The negative impact of rapid urbanization in developing countries has led to a deterioration of urban and regional air quality. Much attention has been given to the impact of fine particulate pollution on urban public health. However, very little attention has been given to its impact on the regional ecosystem such as the agricultural ecosystem. Thus, we evaluate the direct impact of air pollution on the reduction of wheat photosynthesis by fine particulate matter (PM_2.5) pollution in the world’s most heavily polluted area, the North China Plain, using remote sensing observations and ground measurements. We found the following to be true: (1) Heavy PM_2.5 pollution could significantly reduce wheat photosynthesis and cause an expositional relationship between the PM_2.5 concentration and wheat photosynthesis (R² = 0.9824, P < 0.05); (2) Heavy PM_2.5 pollution makes up 2% for the reduction in wheat photosynthesis at all wheat-plant farmlands in the North China Plain, approximately covering an area of 354,400 km²; (3) Increasing heavy PM_2.5 pollution significantly reduced wheat photosynthesis by 87% in wheat-planted farmland during 1999–2011. We hope the results presented here could draw attention to the effect of PM_2.5 pollution on the agricultural ecosystem and encourage further studies to evaluate the feedback of atmospheric pollution on the agricultural ecosystem using remote sensing.

Abbreviation: Northern China Plain (NCP); normalized difference vegetation index (NDVI); The Moderate Resolution Imaging Spectroradiometer (MODIS); fine particulate matter (PM_2.5)     

PM(2.5) induces acute electrocardiographic alterations in healthy rats

There is evidence that changes of the autonomic control of the heart are among the potential mechanisms responsible for pollution-related cardiac mortality. The objective of this work is to assess the acute effects of urban particulate matter of 2.5 microm (PM(2.5)) particles on heart rate (HR) and HR variability. Forty-seven healthy Wistar rats were anesthetized, submitted to tracheal intubation, and instilled with 1 mL of four different solutions: saline, blank filter, and 50 or 100 microg of PM(2.5). PM(2.5) was collected in glass fiber filters using a high-volume sampler. Electrodes for obtaining electrocardiograms were implanted subcutaneously in a Lead II configuration. HR and the standard deviation of the intervals between normal beats (SDNN) were assessed immediately before and 30 and 60 min after instillation. HR decreased significantly (P<0.001) with time, but no significant effect of treatment or interaction between time and treatment was observed. In contrast, there was a significant SDNN interaction between time and treatment (P=0.025). The SDNN decreased 60 min after instillation with a PM(2.5) of 50 and 100 microg. In conclusion, the injection of an aqueous suspension of PM(2.5) induced a reduction of SDNN in healthy rats. The effect was observed 1h after instillation and in a concentration of <100 microg.     

The effect of outdoor air and indoor human activity on mass concentrations of PM(10), PM(2.5), and PM(1) in a classroom

The 12-h mass concentration of PM₁₀, PM_2.5, and PM₁ was measured in a lecturing room by means of three co-located Harvard impactors. The filters were changed at 8 AM and at 8 PM to cover the periods of presence and absence of students. Concentrations were assessed by gravimetry. Ambient PM₁₀ data were available for corresponding 12-h intervals from the nearest state air-quality-monitoring network station. The data were pooled into four periods according to the presence and absence of students—Monday-Thursday day (workday daytime), Monday-Thursday night (workday night), Friday-Sunday day (weekend daytime), and Friday-Sunday night (weekend night). Average indoor workday daytime concentrations were 42.3, 21.9 and 13.7 μg m⁻³, workday night were 20.9, 19.1 and 15.2 μg m⁻³, weekend daytime were 21.9, 18.1 and 11.4 μg m⁻³, and weekend night were 24.5, 21.3, and 15.6 μg m⁻³ for PM₁₀, PM_2.5, and PM₁, respectively. The highest 12-h mean, median, and maximum (42.3, 43.0, and 76.2 μg m⁻³, respectively) indoor concentrations were recorded on workdays during the daytime for PM₁₀. The statistically significant (r=0.68,P<0.0009) correlation between the number of students per hour per day and the indoor coarse fraction calculated as PM_10−2.5 during daytime on workdays indicates that the presence of people is an important source of coarse particles indoor. On workdays, the daytime PM₁₀ indoor/outdoor ratio was positively associated (r=0.93) with an increasing indoor coarse fraction (PM_10-2.5), also indicating that an important portion of indoor PM₁₀ had its source inside the classroom. With the exception of the calculated coarse fraction (PM_10-2.5), all of the measured indoor particulate matter fractions were significantly highly correlated with outdoor PM₁₀ and negatively correlated with wind velocity, showing that outdoor levels of particles influence their indoor concentrations.     

A comparison of particulate matter from biomass-burning rural and non-biomass-burning urban households in northeastern China

BACKGROUND: Biomass fuel is the primary source of domestic fuel in much of rural China. Previous studies have not characterized particle exposure through time-activity diaries or personal monitoring in mainland China. OBJECTIVES: In this study we characterized indoor and personal particle exposure in six households in northeastern China (three urban, three rural) and explored differences by location, cooking status, activity, and fuel type. Rural homes used biomass. Urban homes used a combination of electricity and natural gas. METHODS: Stationary monitors measured hourly indoor particulate matter (PM) with an aerodynamic diameter < or = 10 microm (PM10) for rural and urban kitchens, urban sitting rooms, and outdoors. Personal monitors for PM with an aerodynamic diameter < or = 2.5 microm (PM2.5) were employed for 10 participants. Time-activity patterns in 30-min intervals were recorded by researchers for each participant. RESULTS: Stationary monitoring results indicate that rural kitchen PM10 levels are three times higher than those in urban kitchens during cooking. PM10 was 6.1 times higher during cooking periods than during noncooking periods for rural kitchens. Personal PM2.5 levels for rural cooks were 2.8-3.6 times higher than for all other participant categories. The highest PM2.5 exposures occurred during cooking periods for urban and rural cooks. However, rural cooks had 5.4 times higher PM2.5 levels during cooking than did urban cooks. Rural cooks spent 2.5 times more hours per day cooking than did their urban counterparts. CONCLUSIONS: These findings indicate that biomass burning for cooking contributes substantially to indoor particulate levels and that this exposure is particularly elevated for cooks. Second-by-second personal PM2.5 exposures revealed differences in exposures by population group and strong temporal heterogeneity that would be obscured by aggregate metrics.     

Maternal exposure to ambient PM2.5 and term low birthweight in the State of Georgia

A growing body of evidence suggests that ambient air pollution could be associated with low birthweight (LBW). In this study, we examined pregnancy exposure to ambient PM_2.5 and the risk of LBW in the State of Georgia. The study population consisted of 48,172 full-term live births between 1 January 2004 and 31 December 2004 in nine counties of Georgia, which was obtained from the national natality dataset. County-level air quality index data obtained from the U.S. Environmental Protection Agency was used to estimate exposure to ambient levels of PM_2.5. Multivariate logistic regression revealed that infants with maternal exposure to PM_2.5 falling within 75 to < 95th percentiles were at increased risk of LBW (OR: 1.36; 95 % CI: 1.03, 1.79), after adjusting for potential confounders. This study provided more evidence on the role of PM_2.5 in LBW. Reducing exposure for pregnant women would be necessary to improve the health of infants.     

Predictors of indoor fine particulate matter in infants’ bedrooms in Denmark

Background

Particulate matter (PM) in ambient air is responsible for adverse health effects in adults and children. Relatively little is known about the concentrations, sources and health effects of PM in indoor air.

Objective

To identify sources of fine PM in infants’ bedrooms.

Methods

We conducted 1122 measurements of fine PM (PM_2.5 and black smoke) in the bedrooms of 389 infants and registered indoor activities and characteristics of the house. We used mixed models to identify and quantify associations between predictors and concentrations.

Results

The concentration of PM_2.5 was 2.8 times (95% confidence interval [CI], 1.4–5.5 times) higher in houses where people smoked; the concentration increased by 19% (95% CI, 15–23%) per doubling of the amount of tobacco smoked and decreased by 16% (95% CI, 9–27%) per 5-m increase in the distance between the smoking area and the infant’s bedroom. Frying without a range hood was associated with a 32% (95% CI, 12–54%) higher PM_2.5 concentration per time per day, whereas frying with use of a range hood did not increase the concentration in the infant’s bedroom. Use of a fireplace, stove, candles or vacuum-cleaner, interior rebuilding or renovation, local traffic, inner city residence and cold season increased the fine PM concentration. Open windows decreased the PM_2.5 concentration in homes with smokers but increased the concentration in non-smoking homes.

Conclusions

We identified several sources of fine PM in infants’ bedrooms. The concentrations can be reduced by use of a range hood for frying, by not using candles, a fireplace or a stove, by increasing the distance between the bedroom and the smoking area and by opening windows in houses of smokers. Smoking is a strong predictor of fine PM in infants’ bedrooms and should be avoided.     

Global Estimates of Ambient Fine Particulate Matter Concentrations from Satellite-Based Aerosol Optical Depth: Development and Application

Background

Epidemiologic and health impact studies of fine particulate matter with diameter < 2.5 μm (PM_2.5) are limited by the lack of monitoring data, especially in developing countries. Satellite observations offer valuable global information about PM_2.5 concentrations.

Objective

In this study, we developed a technique for estimating surface PM_2.5 concentrations from satellite observations.

Methods

We mapped global ground-level PM_2.5 concentrations using total column aerosol optical depth (AOD) from the MODIS (Moderate Resolution Imaging Spectroradiometer) and MISR (Multiangle Imaging Spectroradiometer) satellite instruments and coincident aerosol vertical profiles from the GEOS-Chem global chemical transport model.

Results

We determined that global estimates of long-term average (1 January 2001 to 31 December 2006) PM_2.5 concentrations at approximately 10 km × 10 km resolution indicate a global population-weighted geometric mean PM_2.5 concentration of 20 μg/m³. The World Health Organization Air Quality PM_2.5 Interim Target-1 (35 μg/m³ annual average) is exceeded over central and eastern Asia for 38% and for 50% of the population, respectively. Annual mean PM_2.5 concentrations exceed 80 μg/m³ over eastern China. Our evaluation of the satellite-derived estimate with ground-based in situ measurements indicates significant spatial agreement with North American measurements (r = 0.77; slope = 1.07; n = 1057) and with noncoincident measurements elsewhere (r = 0.83; slope = 0.86; n = 244). The 1 SD of uncertainty in the satellite-derived PM_2.5 is 25%, which is inferred from the AOD retrieval and from aerosol vertical profile errors and sampling. The global population-weighted mean uncertainty is 6.7 μg/m³.

Conclusions

Satellite-derived total-column AOD, when combined with a chemical transport model, provides estimates of global long-term average PM_2.5 concentrations.     

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

OBJECTIVES—There is considerable evidence linking ambient particles measured as particulate matter with aerodynamic diameter <10 µm (PM₁₀) to daily mortality and hospital admissions but it is not clear which physical or chemical components of the particle mixture are responsible. The relative effects of fine particles (PM_2.5), coarse particles (PM_2.5-10), black smoke (mainly fine particles of primary origin) and sulphate (mainly fine particles of secondary origin) were investigated, together with ozone, SO₂, NO₂, and CO, on daily mortality and hospital admissions in the west Midlands conurbation of the United Kingdom.
METHODS—Time series of health outcome and environmental data were obtained for the period 1994-6. The relative risk of death or hospital admission was estimated with regression techniques, controlling for long term time trends, seasonal patterns, influenza epidemics, effects of day of the week, and temperature and humidity. Models were adjusted for any remaining residual serial correlation and overdispersion. The sensitivities of the estimates for the effects of pollution to the inclusion of a second pollutant and seasonal interactions (warm or cool) were also examined.
RESULTS—Daily all cause mortality was not associated with any gaseous or particulate air pollutant in the all year analysis, although all measures of particles apart from PM_2.5-10 showed significant positive effects of the warm season. Neither respiratory nor cardiovascular admissions (all ages) were associated with any air pollutant, and there were no important seasonal interactions. However, analysis of admissions by age found evidence for various associations—notably between PM₁₀, PM_2.5, black smoke, SO_2, and ozone (negative) and respiratory admissions in the 0-14 age group. The coarse fraction, PM_2.5-10 differed from PM_2.5 in having smaller and less consistent associations (including several large significant negative associations) and a different lag distribution. The results for black smoke, an indicator of fine primary carbonaceous particles, were very similar to those for PM_2.5, and tended to be more robust in two pollutant models. The effects of sulphate, an indicator of secondary particles, also showed some similarities to those of PM_2.5.
CONCLUSIONS—Clear effects of air pollution on mortality and hospital admissions were difficult to discern except in certain age or diagnostic subgroups and seasonal analyses. It was also difficult to distinguish between different measures of particles. Within these limitations the results suggest that the active component of PM₁₀ resides mostly in the fine fraction and that this is due mainly to primary particles from combustion (mainly vehicle) sources with a contribution from secondary particles. Effects of the coarse fraction cannot be excluded.


Keywords: air pollution particulates; mortality; hospital admissions     

Associations between PM2.5 and Heart Rate Variability Are Modified by Particle Composition and Beta-Blocker Use in Patients with Coronary Heart Disease

Background

It has been hypothesized that ambient particulate air pollution is able to modify the autonomic nervous control of the heart, measured as heart rate variability (HRV). Previously we reported heterogeneous associations between particulate matter with aerodynamic diameter < 2.5 μm (PM_2.5) and HRV across three study centers.

Objectives

We evaluated whether exposure misclassification, effect modification by medication, or differences in particle composition could explain the inconsistencies.

Methods

Subjects with coronary heart disease visited clinics biweekly in Amsterdam, the Netherlands; Erfurt, Germany; and Helsinki, Finland for 6–8 months. The standard deviation (SD) of NN intervals on an electrocardiogram (ECG; SDNN) and high frequency (HF) power of HRV was measured with ambulatory ECG during paced breathing. Outdoor levels of PM_2.5 were measured at a central site. In Amsterdam and Helsinki, indoor and personal PM_2.5 were measured during the 24 hr preceding the clinic visit. PM_2.5 was apportioned between sources using principal component analyses. We analyzed associations of indoor/personal PM_2.5, elements of PM_2.5, and source-specific PM_2.5 with HRV using linear regression.

Results

Indoor and personal PM_2.5 were not associated with HRV. Increased outdoor PM_2.5 was associated with decreased SDNN and HF at lags of 2 and 3 days only among persons not using beta-blocker medication. Traffic-related PM_2.5 was associated with decreased SDNN, and long-range transported PM_2.5 with decreased SDNN and HF, most strongly among persons not using beta blockers. Indicators for PM_2.5 from traffic and long-range transport were also associated with decreased HRV.

Conclusions

Our results suggest that differences in the composition of particles, beta-blocker use, and obesity of study subjects may explain some inconsistencies among previous studies on HRV.     

Effects of Ambient Particulate Matter (PM2.5) Exposure on Calorie Intake and Appetite of Outdoor Workers

Malaysia has been experiencing smoke-haze episodes almost annually for the past few decades. PM_2.5 is the main component in haze and causes harmful impacts on health due to its small aerodynamic size. This study aimed to explore the implications of PM_2.5 exposure on the dietary intake of working individuals. Two phased 13-weeks follow-up study was conducted involving 440 participants, consisting of two cohorts of outdoor and indoor workers. Ambient PM_2.5 concentrations were monitored using DustTrakTM DRX Aerosol Monitor. Data on Simplified Nutritional Appetite Questionnaire (SNAQ) and 24 h diet recall were collected weekly. The highest PM_2.5 concentration of 122.90 ± 2.07 µg/m³ was recorded in August, and it vastly exceeded the standard value stipulated by US EPA and WHO. SNAQ scores and calorie intake were found to be significantly (p < 0.05) associated with changes in PM_2.5 exposure of outdoor workers. Several moderate and positive correlations (R-value ranged from 0.4 to 0.6) were established between SNAQ scores, calorie intake and PM_2.5 exposure. Overall findings suggested that long hours of PM_2.5 exposure affect personal dietary intake, potentially increasing the risk of metabolic syndromes and other undesired health conditions. The current policy should be strengthened to safeguard the well-being of outdoor workers.     

Measurement and modeling of respirable particulate (PM10) and lead pollution over Madurai, India

Samples of particulate matter less than or equal to 10 μm (PM₁₀) were collected round the clock duration by using a respirable dust sampler (APM 460 BL) in Madurai, the second largest and most densely populated city of Tamil Nadu, India. The Environmental Protection Agency (EPA)-recommended standard methods were adopted not only for sample collection but also for subsequent analysis of respirable particulate pollutants. The observed PM₁₀ concentrations varied from 88.1 to 226.9 μg/m³, and lead concentrations ranged between 0.21 to 1.18 μg/m³. The annual averages of the concentrations of the pollutants of current concern manifested that they were mostly below the Indian air quality standards and were generally comparable with those concentrations observed in most other Indian urban areas. The AERMOD model was validated simultaneously by comparing the predicted levels with the estimated levels of PM₁₀. The generated database of the present investigation on the degree of pollution may be used for further research investigation and pollution abatement in the city.     

Potential confounding of particulate matter on the short-term association between ozone and mortality in multisite time-series studies

BACKGROUND: A critical question regarding the association between short-term exposure to ozone and mortality is the extent to which this relationship is confounded by ambient exposure to particles. OBJECTIVES: We investigated whether particulate matter < 10 and < 2.5 microm in aerodynamic diameter (PM(10) and PM(2.5)) is a confounder of the ozone and mortality association using data for 98 U.S. urban communities from 1987 to 2000. METHODS: We a) estimated correlations between daily ozone and daily PM concentrations stratified by ozone or PM levels; b) included PM as a covariate in time-series models; and c) included PM as a covariate as in d), but within a subset approach considering only days with ozone below a specified value. RESULTS: Analysis was hindered by data availability. In the 93 communities with PM(10) data, only 25.0% of study days had data on both ozone and PM(10). In the 91 communities with PM(2.5) data, only 9.2% of days in the study period had data on ozone and PM(2.5). Neither PM measure was highly correlated with ozone at any level of ozone or PM. National and community-specific effect estimates of the short-term effects of ozone on mortality were robust to inclusion of PM(10) or PM(2.5) in time-series models. The robustness remains even at low ozone levels (< 10 ppb) using a subset approach. CONCLUSIONS: Results provide evidence that neither PM(10) nor PM(2.5) is a likely confounder of observed ozone and mortality relationships. Further investigation is needed to investigate potential confounding of the short-term effects of ozone on mortality by PM chemical composition.     

Associations between Ambient Fine Particulate Levels and Disease Activity in Patients with Systemic Lupus Erythematosus (SLE)

Background

Systemic lupus erythematosus (SLE) is a chronic disease of unclear etiology, characterized by an overactive immune system and the production of antibodies that may target normal tissues of many organ systems, including the kidneys. It can arise at any age and occurs mainly in women.

Objective

Our aim was to evaluate the potential influence of particulate matter (PM) air pollution on clinical aspects of SLE.

Methods

We studied a clinic cohort of SLE patients living on the island of Montreal, followed annually with a structured clinical assessment. We assessed the association between ambient levels of fine PM [median aerodynamic diameter ≤ 2.5 μm (PM_2.5)] measured at fixed-site monitoring stations and SLE disease activity measured with the SLE Disease Activity Index, version 2000 (SLEDAI-2K), which includes anti–double-stranded DNA (anti-dsDNA) serum-specific autoantibodies and renal tubule cellular casts in urine, which reflects serious renal inflammation. We used mixed effects regression models that we adjusted for daily ambient temperatures and ozone levels.

Results

We assessed 237 patients (223 women) who together had 1,083 clinic visits from 2000 through 2007 (mean age at time of first visit, 41.2 years). PM_2.5 levels were associated with anti-dsDNA and cellular casts. The crude and adjusted odds ratios (reflecting a 10-μg/m³ increase in PM_2.5 averaged over the 48 hr prior to clinical assessment) were 1.26 [95% confidence interval (CI), 0.96–1.65] and 1.34 (95% CI, 1.02–1.77) for anti-dsDNA antibodies and 1.43 (95% CI, 1.05–1.95) and 1.28 (0.92–1.80) for cellular casts. The total SLEDAI-2K scores were not associated with PM_2.5 levels.

Conclusions

We provide novel data that suggest that short-term variations in air pollution may influence disease activity in established autoimmune rheumatic disease in humans. Our results add weight to concerns that pollution may be an important trigger of inflammation and autoimmunity.     

Induction of IL-6 and inhibition of IL-8 secretion in the human airway cell line Calu-3 by urban particulate matter collected with a modified method of PM sampling

Exposure to particulate matter (PM) induces inflammatory cytokines. In the present study, we evaluated the secretion of IL-6 and IL-8 by an airway cell line exposed to PM with a mean aerodynamic size equal to or less than 10 or 2.5 μm (PM₁₀ and PM_2.5, respectively) collected in Mexico City, using a modified high-volume sampling method avoiding the use of solvents or introducing membrane components into the samples. PM was collected on cellulose-nitrate (CN) membranes modified for collection on high-volume samplers. Composition of the particles was evaluated by particle-induced X-ray emission (PIXE) and scanning electron microscopy. The particles (10-160 μg/cm²) were tested on Calu-3 cells. Control cultures were exposed to LPS (10 ng/mL to 100 μg/mL) or silica (10-160 μg/cm²). IL-6 and IL-8 secretions were evaluated by ELISA. An average of 10 mg of PM was recovered form each cellulose-nitrate filter. No evidence of contamination from the filter was found. Cells exposed to PM₁₀ presented an increase in the secretion of IL-6 (up to 400%), while IL-8 decreased (from 40% to levels below the detection limit). A similar but weaker effect was observed with PM_2.5. In conclusion, our modified sampling method provides a large amount of urban PM free of membrane contamination. The urban particles induce a decrease in IL-8 secretion that contrasts with the LPS and silica effects. These results suggest that the regulation of IL-8 expression is different for urban particles (complex mixture containing combustion-related particles, soil and biologic components) than for biogenic compounds or pure mineral particles.     

Relationship between fine particulate matter events with respect to synoptic weather patterns and the implications for circulatory and respiratory disease in Taipei,Taiwan

The aim of the study is to assess the relationship between PM_2.5, synoptic weather patterns, and admissions for circulatory and respiratory disease. A PM_2.5 event is defined as a day when the daily mean PM_2.5 concentration exceeds 65?μg/m³. PM_2.5 events that coincided with the occurrence of PM attributed to Asian dust storm (ADS) and photochemical smog (PCS) were removed from the study in order to focus solely on the health effects from PM_2.5. A one-tailed z-test and a relative risk (RR) estimate were performed. Hospital admissions for respiratory diseases were greater than those for circulatory diseases, and asthma-related diseases had a higher impact in the Adults group, and the maximum RR was 1.94 [1.37 2.77] on the first day after the event. It is evident that PM_2.5 episodes connected to particular synoptic weather patterns pose a risk to health as large as ADS and PCS events.     

Particulate matter, DNA methylation in nitric oxide synthase, and childhood respiratory disease

Background: Air pollutants have been associated with childhood asthma and wheeze. Epigenetic regulation of nitric oxide synthase-the gene responsible for nitric oxide production-may be affected by air pollutants and contribute to the pathogenesis of asthma and wheeze.Objective: Our goal was to investigate the association between air pollutants, DNA methylation, and respiratory outcomes in children.Methods: Given residential address and buccal sample collection date, we estimated 7-day, 1-month, 6-month, and 1-year cumulative average PM2.5 and PM10 (particulate matter ≤ 2.5 and ≤ 10 μm aerodynamic diameter, respectively) exposures for 940 participants in the Children's Health Study. Methylation of 12 CpG sites in three NOS (nitric oxide synthase) genes was measured using a bisulfite-polymerase chain reaction Pyrosequencing assay. Beta regression models were used to estimate associations between air pollutants, percent DNA methylation, and respiratory outcomes.Results: A 5-μg/m3 increase in PM2.5 was associated with a 0.20% [95% confidence interval (CI): -0.32, -0.07] to 1.0% (95% CI: -1.61, -0.56) lower DNA methylation at NOS2A position 1, 0.06% (95% CI: -0.18, 0.06) to 0.58% (95% CI: -1.13, -0.02) lower methylation at position 2, and 0.34% (95% CI: -0.57, -0.11) to 0.89% (95% CI: -1.57, -0.21) lower methylation at position 3, depending on the length of exposure and CpG locus. One-year PM2.5 exposure was associated with 0.33% (95% CI: 0.01, 0.65) higher in average DNA methylation of 4 loci in the NOS2A CpG island. A 5-μg/m3 increase in 7-day and 1-year PM2.5 was associated with 0.6% (95% CI: 0.13, 0.99) and 2.8% (95% CI: 1.77, 3.75) higher NOS3 DNA methylation. No associations were observed for NOS1. PM10 showed similar but weaker associations with DNA methylation in these genes.Conclusions: PM2.5 exposure was associated with percent DNA methylation of several CpG loci in NOS genes, suggesting an epigenetic mechanism through which these pollutants may alter production of nitric oxide.     

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.     

Apheis: Health Impact Assessment of Long-term Exposure to PM2.5 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 μm) 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 μg/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.