Abstract:
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Since the passage of the 1990 Clean Air Act Amendments, significant improvements in air quality have been observed throughout the United States. Using mediation analysis, we quantify the reduction of cardiovascular mortality rates in US counties that can be attributable to reduction in annual average concentrations of fine particulate matter (PM2.5) between 1990 and 2010. We attribute approximately 7.8% of the trend in reduced cardiovascular deaths to reduction trend in PM2.5 concentrations. We further examine which PM2.5 components and their emission sectors most efficiently mediate the PM2.5-related cardiovascular mortality trend. We determine that particulate sulfate concentrations due to sulfur dioxide emissions contribute the most to the reduction in total PM2.5-related cardiovascular mortality, but reducing elemental carbon exposure is more efficient at reducing cardiovascular mortality on per unit mass basis. [The statements in this abstract do not necessarily reflect the views of the EPA.]
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