Climate-driven PM2.5 and ozone change and their associated health exposure over continental US in 2050s

Abstract:

We propose to use Environmental Benefits Mapping and Analysis Program Community Edition (BenMAP-CE) to evaluate the PM_2.5- and ozone-related short and long term mortality at present (2000s) and in the future (2050s) over the continental United States. Atmospheric chemical fields are simulated by WRF-CMAQ (horizontal resolution: 12km × 12km), applying the dynamical downscaling technique from a global climate-chemistry model under the Representative Concentration Pathways scenario (RCP 8.5). Future air quality results predict that the annual mean PM_2.5 concentration will decrease nationwide, especially in the eastern US and west coast. However, the ozone concentration is projected to decrease in the Eastern US but increase in the Western US. Future mortality is assessed under two scenarios (1) holding future population and baseline incidence rate at the present level and (2) using the projected baseline incidence rate and population in 2050. For PM_2.5, the entire continental US presents a decreasing trend of PM_2.5-related mortality by the 2050s in Scenario (1), primarily resulting from the emissions reduction. While in Scenario (2), almost half of the continental states show a rising tendency of PM_2.5-related mortality, due to the dominant influence of population growth. In particular, the highest PM_2.5-related deaths and the biggest discrepancy between present and future PM_2.5-related deaths will both occur in California in 2050s. For the ozone-related premature mortality, the simulation shows nation-wide rising tendency in 2050s under both two scenarios, mainly due to the projected increase of methane, ozone concentration and population.