AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
The Effect of Climate Change on Future PM2.5 Concentrations
DANIEL WESTERVELT, Larry Horowitz, Vaishali Naik, Denise Mauzerall, Princeton University
Abstract Number: 328 Working Group: Aerosols, Clouds, and Climate
Abstract Climate change can influence fine particulate matter concentrations (PM$_(2.5)) through changes in precipiation, temperature, and other meteorological variables. The extent of which climate change will exacerbate or alleviate air pollution in the future is an important aspect of robust climate and air pollution policy decision-making. To determine the influence of climate on PM$_(2.5), we use the Geophysical Fluid Dynamics Laboratory Climate Model version 3 (GFDL CM3), a fully-coupled chemistry-climate model, coupled with future emissions and concentrations provided by the four Representative Concentration Pathways (RCPs). For each of the RCP future simulations, emissions of aerosols and their precursors are held fixed such that only climate (and thus meteorology) can influence PM$_(2.5) surface concentrations. We find a spatially consistent but minimal increase in global PM$_(2.5) of 0.24 µg m$^(-3) for RCP8.5, the most realistic future scenario based on current emissions. Changes in global PM$_(2.5) are at a maximum in the fall and are mainly controlled by sulfate followed by organic carbon with minimal influence of black carbon. RCP2.6 is the only scenario that projects a decrease in global PM$_(2.5) with future climate changes, albeit only by -0.03 µg m$^(-3) by the end of the 21st century. Regional and local changes in PM2.5 are larger, reaching upwards of 2 µg m$^(-3) for certain locations on an annually averaged basis in RCP8.5. Using multivariate linear regression, we find that future PM$_(2.5) are most sensitive to precipitation, temperature, and wind. Fine particulate matter concentrations and temperature are found to be robustly positively associated, while negatively related with precipitation and wind speed. We conclude that the hypothesized “climate penalty” of future increases in fine particulate matter is relatively minor on a global scale compared to the influence of emissions on PM$_(2.5) concentrations. Our projected larger regional changes may exacerbate local air pollution related mortality, suggesting that climate policies reducing greenhouse gas emissions will be beneficial for human health in addition to policies reducing traditional air pollutants.