Modeling Regional & Global Atmospheric Chemistry Mechanisms: Observing Adverse Respiratory Health Effects due to Air Pollution from Modeling Output

Atmospheric chemistry models are used for air quality forecasting and these require chemical reaction mechanisms to simulate the production of air pollution. Chemical boundary conditions are necessity for regional scale simulations. Global models may be used to provide boundary conditions to regional models. NOAA/NCEP uses the Community Multi-scale Air Quality Model  (CMAQ) for air quality forecasting and one of its standard chemical mechanisms is the Regional Atmospheric Chemistry Mechanism, Version 2  (RACM2). The goal of this project is to develop the Global Atmospheric Chemistry Mechanism (GACM), a global version of RACM2. GACM is intended for use in global scale atmospheric chemistry models to provide chemical boundary conditions for regional scale simulations by models such as CMAQ. GACM includes additional chemistry for marine environments while reducing its detailed treatment of organic compounds from anthropogenic sources to keep GACM’s size small enough for global models. GACM’s chemistry of volatile organic compounds (VOC) is highly compatible with the VOC chemistry in RACM2 allowing a global model with GACM to provide VOC boundary conditions to a regional scale model with RACM2 with reduced error.

         The GACM-RACM2 system of mechanisms should yield more accurate regional scale air quality forecasts. The main objectives of this project are to develop GACM and to compare model simulations made with GACM to those made with RACM2 and compared with available data. Simulations will be made with chemical box models that focus on atmospheric chemistry in the absence of meteorology and also with meteorological transport – transformation models such as CMAQ and the 3-D Weather Research & Forecasting Model coupled with chemistry (WRF-Chem). Finally the air quality model simulations will be analyzed with the EPA’s Environmental Benefits Mapping & Analysis Program – Community Edition (BenMAP-CE) to estimate the human health impact and economic value of air quality changes. BenMAP-CE will be used to estimate the human health impacts from simulations made by WRF-Chem with RACM2. Next BenMAP-CE will be used to estimate human health impacts from WRF-Chem simulations made with the combined WRF-Chem / GACM-RACM2 system. Finally the two sets of human health impacts will be compared.