Effects Of Wildfire Smoke On Community Population Health In The Western Us

Abstract

Introduction: Wildfires may be a hazard to human health due to the high levels of airborne particulate matter (PM) released from wildfire smoke. However, the health effects of wildfire-emitted fine particles are not well understood and most of the current studies on wildfire and health are based on single wildfire episode. Further, wildfires are anticipated to increase under climate change. This study uses large-scale wildfire smoke data over six years to estimate the health effect of PM specifically from wildfire smoke in the Western US. Methods: We estimated daily PM2.5 concentrations from wildfires (2004-2009) for every county in the Western US (561 counties) using outputs from the state-of-science GEOS-Chem (v9-01-03) global chemical transport model that utilized daily emissions from the Global Fire Emissions Database (GFED3). We demonstrated spatial exposure patterns in an interactive map. The wildfire-specific PM2.5 data were linked to the Medicare data (=65y) in 122 most populated Western US counties. We used a generalized linear mixed model to estimate the relative risk of hospital admissions on days with high wildfire-specific PM compared to matched comparison days for respiratory and cardiovascular admissions. Results: We estimate that about 57 million people were exposed to wildfire smoke between 2004 and 2009 in the Western US, among which 12% are =64 years. Among the Medicare population, respiratory hospital admissions increased 5.0% on days with wildfire smoke (95% CI: 0.91%-9.26%) compared to non-fire days. Cardiovascular hospital admissions did not show significant association with wildfire smoke. Conclusion: This multi-year, multi-county study is the most comprehensive study to date on wildfire smoke and public health in North America. Results indicate health impacts of PM2.5 from wildfires in elderly population in the Western US. The results provide policy reference on establishing or modifying public health programs in susceptible regions.