PNNL

Abstract

Limited research has been conducted on the contributions of local and non-local emission sources to ambient fine particulate matter (PM2.5) and ozone (O3) and their associated mortality. In this study, we estimated the total mortality impacts of PM2.5 and O3 exposures in California in 2012 with multiple concentration response functions (CRFs), and attributed the estimated mortality to different emission groups. PM2.5 exposures in California were estimated to be associated with a range of 12,700 [95% Confidence Interval (CI): 3,100– 24,300] to 26,700 (95% CI: 18,800 – 35,000) mortalities. In-state anthropogenic emissions were responsible for 53% of the total PM2.5-associated mortality. Based on new epidemiological evidence, we estimated that O3 could be associated with 13,700 (95% CI: 6,100-23,700) mortalities in California, of which 7,300 (95% CI: 2,900-11,000) were diseases from the respiratory system. In addition, 75% of the ambient O3 in California was due to distant emissions outside western United States, leading to 92% of O3-associated mortality. Overall, distant emissions lead to higher mortality burdens of air pollution in California than local anthropogenic emissions.