Analysis of the Co-benefits of Greenhouse Gas Abatement for Global and US Air Quality under Future Climate ScenariosEPA Grant Number: R834285
Title: Analysis of the Co-benefits of Greenhouse Gas Abatement for Global and US Air Quality under Future Climate Scenarios
Investigators: West, J. Jason , Emmons, Louisa , Hanna, Adel , Horowitz, Larry W. , Smith, Steven J. , Vizuete, William
Institution: University of North Carolina at Chapel Hill
Current Institution: University of North Carolina at Chapel Hill , NOAA Geophysical Fluid Dynamics Laboratory , National Center for Atmospheric Research , Pacific Northwest National Laboratory
EPA Project Officer: Chung, Serena
Project Period: September 1, 2009 through August 31, 2013
Project Amount: $300,000
RFA: Adaptation for Future Air Quality Analysis and Decision Support Tools in Light of Global Change Impacts and Mitigation (2008) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Global Climate Change , Climate Change , Air
The proposed research will use a combination of global and regional chemical transport models (CTMs) to analyze the co-benefits of actions to reduce greenhouse gas (GHG) emissions on air quality, globally and in the US.
Actions to reduce emissions of GHGs will affect air quality directly through reductions in emissions of co-emitted air pollutants, and indirectly through changes in global climate. Research on the effects of climate change on air quality has emphasized meteorological downscaling to translate future climate change from general circulation models (GCMs) to a regional scale. Here we propose to emphasize methods of chemical downscaling, in which future climate and pollutant emissions will be simulated in a global CTM, to provide initial and boundary conditions for a US-focused regional CTM. We use these methods to address the air quality co-benefits of actions to reduce GHG emissions, both globally and in the US, by analyzing the mitigation of methane emissions and the control of GHGs generally, in future scenarios to 2050.
While global models have simulated the dependence of global ozone concentrations on methane emissions, the effect of these background changes in urban areas is unknown. We propose to use a system of models to address the effects of global methane mitigation on ozone air quality globally and in the US at fine resolution, under future climate conditions to 2050. The system of models will include the global CTM MOZART-4, and a regional meteorological model (WRF) and CTM (CMAQ) focused on the US, with future climate conditions from a global GCM. Second, we propose to conduct the first model-based analysis of the global co-benefits of actions to reduce GHG emissions on ozone and particulate matter air quality, and the first assessment of co-benefits due to both changes in co-emitted air pollutants and changes in climate. We will use the new Representative Concentration Pathway (RCP) scenarios and work with an energy-economics modeler on our team, such that scenarios to 2050 of air pollutant emissions are fully consistent with projected global actions to reduce GHGs. We will use results of a global GCM to give future climate conditions under these scenarios, and this will drive our system of global and regional models to assess air quality co-benefits globally and downscaled for greater resolution in the US. We will also analyze the relative importance of GHG mitigation within versus outside of the US, and of changes in co-emitted air pollutants versus changes in climate.
We provide a methodological improvement in chemical downscaling, addressing the translation of global to regional scale effects, which will be important in adapting current air quality modeling systems to global change. We likewise analyze important technology and policy choices by quantifying the co-benefits of global actions to reduce GHG emissions (both methane and GHGs generally) on air quality globally and in the US, accounting for both changes in co-emitted pollutants and effects on air quality through changes in climate.