Estimating the health effects of air pollutants : a method with an application to Jakarta

To develop efficient strategies for pollution control, it is essential to assess both the costs of control and the benefits that may result. These benefits will often included improvements in public health, including reductions in both morbidity and premature mortality. Until recently, there has been little guidance about how to calculate the benefits of air pollution controls and how to use those estimates to assign priorities to different air pollution control strategies. The author describes a method for quantifying the benefits of reduced ambient concentrations of pollutants (such as ozone and particulate matter) typically found in urban areas worldwide. The author then applies the method to data on Jakarta, Indonesia, an area characterized by little wind, high population concentration (8 million people), congested roads, and ambient air pollution. The magnitude of the benefits of pollution control depend on the level of air pollution, the expected effects on health of the pollutants (dose-response), the size of the population affected and the economic value of these effects. The results for Jakarta suggest that significant benefits result from reducing exposure to both outdoor and indoor air pollutants. For example, if annual concentrations of particulate matter were reduced to the midpoint of the World Health Organization guideline (and former U.S. ambient standard), the estimates indicate a reduction per year of 1,400 premature deaths (with a range of 900 to 1,900), 49,000 emergency room visits, 600,000 asthma attacks, 7.6 million restricted activity days (including work loss), 124,000 cases of bronchitis in children, and 37 million minor respiratory symptoms. In the case of Jakarta, the methodology suggests that reducing exposure to lead and nitrogen dioxide should also be a high priority. An important consequence of ambient lead pollution is a reduction in learning abilities for children, measured as I.Q loss. Apart from that, reducing the proportion of respirable particles can reduce the amount of illness and premature mortality. Clearly, air pollution represents a significant public health hazard to residents of Jakarta and other cities consistently exposed to high levels of air pollution, such as Bangkok, Mexico City, and Santiago, Chile.Health Monitoring&Evaluation,Montreal Protocol,Air Quality&Clean Air,Environmental Economics&Policies,Pollution Management&Control

Air Pollution and Lost Work

A Poisson specification of the relationship between atmospheric pollution and lost work days is estimated.An important feature of the procedure is control for city-specific effects. A major source of ambiguity in interpreting the results of observational data on pollution versus health status or death rates is that pollution in a city may be correlated with other characteristics ofthat city that affect these outcomes but are not controlled for in the analysis. Or, individual attributes of residents may be correlated with pollution levels but notaccounted for in the analysis. Our results suggest a statistically significantand quantitatively important effect of total suspended particulates on work days lost. A standard deviation increase in total suspended particulates is associated with approximately a ten percent increase in work days lost. As a concomitant of our analysis, we also find a substantial relationship between smoking by others in the individual's household and work days lost by non-smokers.

The Effects of Components of Fine Particulate Air Pollution on Mortality in California: Results from CALFINE

OBJECTIVE: Several epidemiologic studies provide evidence of an association between daily mortality and particulate matter < 2.5 μm in diameter (PM(2.5)). Little is known, however, about the relative effects of PM(2.5) constituents. We examined associations between 19 PM(2.5) components and daily mortality in six California counties. DESIGN: We obtained daily data from 2000 to 2003 on mortality and PM(2.5) mass and components, including elemental and organic carbon (EC and OC), nitrates, sulfates, and various metals. We examined associations of PM(2.5) and its constituents with daily counts of several mortality categories: all-cause, cardiovascular, respiratory, and mortality age > 65 years. Poisson regressions incorporating natural splines were used to control for time-varying covariates. Effect estimates were determined for each component in each county and then combined using a random-effects model. RESULTS: PM(2.5) mass and several constituents were associated with multiple mortality categories, especially cardiovascular deaths. For example, for a 3-day lag, the latter increased by 1.6, 2.1, 1.6, and 1.5% for PM(2.5), EC, OC, and nitrates based on interquartile ranges of 14.6, 0.8, 4.6, and 5.5 μg/m(3), respectively. Stronger associations were observed between mortality and additional pollutants, including sulfates and several metals, during the cool season. CONCLUSION: This multicounty analysis adds to the growing body of evidence linking PM(2.5) with mortality and indicates that excess risks may vary among specific PM(2.5) components. Therefore, the use of regression coefficients based on PM(2.5) mass may underestimate associations with some PM(2.5) components. Also, our findings support the hypothesis that combustion-associated pollutants are particularly important in California

Fine Particulate Air Pollution and Mortality in Nine California Counties: Results from CALFINE

Many epidemiologic studies provide evidence of an association between daily counts of mortality and ambient particulate matter < 10 μm in diameter (PM(10)). Relatively few studies, however, have investigated the relationship of mortality with fine particles [PM < 2.5 μm in diameter (PM(2.5))], especially in a multicity setting. We examined associations between PM(2.5) and daily mortality in nine heavily populated California counties using data from 1999 through 2002. We considered daily counts of all-cause mortality and several cause-specific subcategories (respiratory, cardiovascular, ischemic heart disease, and diabetes). We also examined these associations among several subpopulations, including the elderly (> 65 years of age), males, females, non-high school graduates, whites, and Hispanics. We used Poisson multiple regression models incorporating natural or penalized splines to control for covariates that could affect daily counts of mortality, including time, seasonality, temperature, humidity, and day of the week. We used meta-analyses using random-effects models to pool the observations in all nine counties. The analysis revealed associations of PM(2.5) levels with several mortality categories. Specifically, a 10-μg/m(3) change in 2-day average PM(2.5) concentration corresponded to a 0.6% (95% confidence interval, 0.2–1.0%) increase in all-cause mortality, with similar or greater effect estimates for several other subpopulations and mortality subcategories, including respiratory disease, cardiovascular disease, diabetes, age > 65 years, females, deaths out of the hospital, and non-high school graduates. Results were generally insensitive to model specification and the type of spline model used. This analysis adds to the growing body of evidence linking PM(2.5) with daily mortality

Coarse Particles and Heart Rate Variability among Older Adults with Coronary Artery Disease in the Coachella Valley, California

Alterations in cardiac autonomic control, assessed by changes in heart rate variability (HRV), provide one plausible mechanistic explanation for consistent associations between exposure to airborne particulate matter (PM) and increased risks of cardiovascular mortality. Decreased HRV has been linked with exposures to PM(10) (PM with aerodynamic diameter ≤ 10 μm) and with fine particles (PM with aerodynamic diameter ≤ 2.5 μm) originating primarily from combustion sources. However, little is known about the relationship between HRV and coarse particles [PM with aerodynamic diameter 10–2.5 μm (PM(10–2.5))], which typically result from entrainment of dust and soil or from mechanical abrasive processes in industry and transportation. We measured several HRV variables in 19 nonsmoking older adults with coronary artery disease residing in the Coachella Valley, California, a desert resort and retirement area in which ambient PM(10) consists predominantly of PM(10–2.5). Study subjects wore Holter monitors for 24 hr once per week for up to 12 weeks during spring 2000. Pollutant concentrations were assessed at nearby fixed-site monitors. We used mixed models that controlled for individual-specific effects to examine relationships between air pollutants and several HRV metrics. Decrements in several measures of HRV were consistently associated with both PM(10) and PM(10–2.5); however, there was little relationship of HRV variables with PM(2.5) concentrations. The magnitude of the associations (~ 1–4% decrease in HRV per 10-μg/m(3) increase in PM(10) or PM(10–2.5)) was comparable with those observed in several other studies of PM. Elevated levels of ambient PM(10–2.5) may adversely affect HRV in older subjects with coronary artery disease