American Journal of Epidemiology Advance Access originally published online on February 25, 2008
American Journal of Epidemiology 2008 167(8):986-997; doi:10.1093/aje/kwm396
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ORIGINAL CONTRIBUTIONS |
Effect Modification by Community Characteristics on the Short-term Effects of Ozone Exposure and Mortality in 98 US Communities
1 School of Forestry and Environmental Studies, Yale University, New Haven, CT
2 Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
Correspondence to Dr. Michelle L. Bell, School of Forestry and Environmental Studies, Yale University, 205 Prospect Street, New Haven, CT 06511 (e-mail: michelle.bell{at}yale.edu).
Received for publication April 26, 2006. Accepted for publication December 17, 2007.
Previous research provided evidence of an association between short-term exposure to ozone and mortality risk and of heterogeneity in the risk across communities. The authors investigated whether this heterogeneity can be explained by community-specific characteristics: race, income, education, urbanization, transportation use, particulate matter and ozone levels, number of ozone monitors, weather, and use of air conditioning. Their study included data on 98 US urban communities for 1987 to 2000 from the National Morbidity, Mortality, and Air Pollution Study; US Census; and American Housing Survey. On average across the communities, a 10-ppb increase in the previous week's ozone level was associated with a 0.52% (95% posterior interval: 0.28, 0.77) increase in mortality. The authors found that community-level characteristics modify the relation between ozone and mortality. Higher effect estimates were associated with higher unemployment, fraction of the Black/African-American population, and public transportation use and with lower temperatures or prevalence of central air conditioning. These differences may relate to underlying health status, differences in exposure, or other factors. Results show that some segments of the population may face higher health burdens of ozone pollution.
air conditioning; air pollution; continental population groups; income; mortality; ozone; particulate matter; socioeconomic factors
Abbreviations: PM2.5, particulate matter with an aerodynamic diameter of
2.5 µm; PM10, particulate matter with an aerodynamic diameter of 10 µm