A historical analysis of heat waves over the continental US and their impact on regional air quality

Abstract:

Climate change is expected to increase the frequency and intensity of extreme weather events across the United States. Heat waves, in particular, are expected to increase significantly over the coming decades. This may have important implications for regional air pollution, particularly due to the relationship between ambient temperatures and surface ozone concentrations during the summer. Ozone levels already exceed the National Ambient Air Quality Standards (NAAQS) across many regions in the US, making it important to characterize this relationship in order to accurately inform future efforts towards mitigating this problem. In this study, the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2) assimilated meteorology product is used to identify geographic and temporal trends in heat waves in the continental US from 1980 to 2018. EPA Air Quality System (AQS) data is also used to study the relationship between these trends and observed ozone concentrations. The GEOS-Chem chemical transport model is then used to isolate the impact of regional heatwaves on ozone concentrations with the goal of providing process-level insight into the nature of these interactions.