Secondary organic aerosol association with cardiorespiratory disease mortality in the United States

Abstract Fine particle pollution, PM 2.5 , is associated with increased risk of death from cardiorespiratory diseases. A multidecadal shift in the United States (U.S.) PM 2.5 composition towards organic aerosol as well as advances in predictive algorithms for secondary organic aerosol (SOA) allows for novel examinations of the role of PM 2.5 components on mortality. Here we show SOA is strongly associated with county-level cardiorespiratory death rates in the U.S. independent of the total PM 2.5 mass association with the largest associations located in the southeastern U.S. Compared to PM 2.5 , county-level variability in SOA across the U.S. is associated with 3.5× greater per capita county-level cardiorespiratory mortality. On a per mass basis, SOA is associated with a 6.5× higher rate of mortality than PM 2.5 , and biogenic and anthropogenic carbon sources both play a role in the overall SOA association with mortality. Our results suggest reducing the health impacts of PM 2.5 requires consideration of SOA.