Global/regional climate change and air quality are closely coupled through many chemical, radiative, and land surface processes. While climate response to changes in atmospheric gases and aerosols has been extensively studied in the past several decades, studies that focus on the impact of global/regional climate change on air quality are limited. A changing climate can affect air quality through a number of processes including (1) changes in global through urban climate variables/phenomena (e.g., surface air temperature, downward solar radiation, precipitation frequency, stagnation events, and ventilation) that affect emissions, chemical reactions, and transport processes of pollutants, and (2) changes in vegetation and land covers that alter biogenic and anthropogenic emissions, dry deposition, and pollution export from the urban/regional to global environment.

In this work, the impact of regional climate change on air quality is studied using the U.S. EPA Models-3/Community Multiscale Air Quality (CMAQ) modeling system. The meteorological inputs for CMAQ were generated with a regional climate model based on the Penn State/NCAR Mesoscale Model (MM5). CMAQ simulations are being conducted at a horizontal grid resolution of 36-km for a domain covering the contiguous U.S., part of Canada and Mexico, and the surrounding oceans for 10 summers (June-August) in 1998-2002 and 2048-2052, where the future climate is simulated based on the Intergovernmental Panel on Climate Change (IPCC) A1B scenario. The response of biogenic emissions to vegetation changes as a result of the changing climate is estimated using MM5 simulations and the Sparse Matrix Operator Kernel Emissions (SMOKE) Modeling System. The results are analyzed to characterize the changes in air quality due to changing climate through the aforementioned processes for the current (1999-2002) and future (2048-2052) climate scenarios.