Estimation of long-term area-average PM2.5 concentrations for area-level health analyses

Introduction: There is increasing evidence of the association between individual long-term PM2.5 exposure and human health. Mortality and morbidity data collected at the area-level are valuable resources for investigating corresponding population-level health effects. However, PM2.5 monitoring data are available for limited periods of time and locations, and are not adequate for estimating area-level concentrations. We developed a general approach to estimate county-average concentrations representative of population exposures for 1980-2010 in the continental U.S. We chose the year 2000 as a test case for this analysis. Methods: We predicted 2000 annual average PM2.5 concentrations on a 25 kilometer national grid consisting of 12,501 unique locations, using a historical point prediction model previously developed for estimating annual average PM2.5 concentrations in the continental U.S. for 1980-2010. We used spatial interpolation of the national grid predictions to estimate PM2.5 concentrations at all 29...