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Significantly reduced health burden from ambient air pollution in the United States under emission reductions from 1990 to 2010
Zhang, Y., J. West, R. Mathur, J. Xing, C. Hogrefe, S. Roselle, J. Bash, Jon Pleim, M. Gan, AND David-C Wong. Significantly reduced health burden from ambient air pollution in the United States under emission reductions from 1990 to 2010. 16th Annual CMAS Conferenct, Chapel Hill, North Carolina, October 23 - 25, 2017.
By combining detailed CMAQ simulations of trends in air pollutant concentrations across the U.S. over the past two decades with a health assessment model, this study analyses long-term trends in air pollution associated premature mortality and demonstrates the success of Agency actions, directed at reducing emissions of ambient PM2.5 and O3 precursors, on reducing human exposure to air pollution and improving public health.
The 2015 Global Burden of Disease (GBD) study has listed air pollution as the fourth-ranking global mortality risk factor. Many studies have estimated the global or national burden of disease attributed to air pollution. However, little effort has been focused on understanding how these burdens change through time, especially in the United States (US). Here we aim to estimate air pollution-related mortality in the continental US for each year from 1990 to 2010, to understand the trend over this time period. We also analyze the relative contributions of changes in air pollutant concentrations, population, and baseline mortality to the overall trend and to the inter-annual variability in mortality estimates. To achieve this goal, we use a 21-year model simulation of PM2.5 and O3 concentrations from 1990 to 2010, with grid resolution of 36km x 36km. We also use annual county-level baseline mortality rates and population data archived by the US Centers for Disease Control (CDC). We find that the PM2.5-related mortality burden from ischemic heart disease, chronic obstructive pulmonary disease, lung cancer, and stroke, has steadily decreased, with a reduction of 54% from 1990 to 2010. The PM2.5 -related mortality burden would have decreased only by 26% if the PM2.5 concentrations had not decreased from 1990, due to decreases in baseline mortality rates for major diseases affected by PM2.5. The mortality burden associated with O3 for chronic respiratory disease has larger inter-annual variations than the PM2.5-related burden, primarily due to inter-annual variations in O3 mixing ratios. The O3-related mortality burden has increased by 28% from 1990 to 2010, despite ozone decreases, mainly due to increases in the baseline mortality rates and population. The O3-related mortality burden would have increased by 59% if the O3 concentration was kept constant at the 1990 level. We concluded that the air quality changes have significantly accelerated (or decelerated) the decreasing (or increasing) trends for PM2.5?-(or O3-) related mortality burden change for the past 2 decades.