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FORECASTING AIR QUALITY OVER THE UNITED STATES
Citation:
Schere, K L. FORECASTING AIR QUALITY OVER THE UNITED STATES. Presented at Science Forum 2003, Washington, DC, May 5-7, 2003.
Impact/Purpose:
The objectives of this task are to continuously develop and improve EPA's mesoscale (regional through urban scale) air quality simulation models, such as the Community Multiscale Air Quality (CMAQ) model, as air quality management and NAAQS implementation tools. CMAQ is a multiscale and multi-pollutant chemistry-transport model (CTM) that includes the necessary critical science process modules for atmospheric transport, deposition, cloud mixing, emissions, gas- and aqueous-phase chemical transformation processes, and aerosol dynamics and chemistry. To achieve the advances in CMAQ, research will be conducted to develop and test appropriate chemical and physical mechanisms, improve the accuracy of emissions and dry deposition algorithms, and to develop and improve state-of-the-science meteorology models and contributing process parameterizations.
Description:
Increased awareness of national air quality issues on the part of the media and the general public have recently led to more demand for short-term (1-2 day) air quality forecasts for use in assessing potential health impacts (e.g., on children, the elderly, and asthmatics) and potential mitigation actions in local communities (e.g., increased use of carpools and mass transit, decreased industrial operations). An emerging collaborative partnership between U.S. EPA and the National Oceanic and Atmospheric Administration (NOAA) will bring the strengths of these two Agencies' capabilities in atmospheric measurements and modeling in developing an operational capability for producing national modeling guidance for short-term air quality forecasts for ozone and particulate matter. EPA will contribute through its national assimilation, analysis, and dissemination of ambient air quality data and emissions data, as well as its air quality modeling capability. NOAA brings expertise in operational meteorological modeling and product development and dissemination. Local air quality forecasts will be made by state and local air quality management agencies, based in part upon the national guidance provided by the EPA/NOAA partnership. The initial operational capability will provide 1-2 day ozone forecast guidance for the Northeast U.S. on a daily basis by September 2004. Model development and testing of the operational system will be conducted from now through the summer 2004 ozone season.
The initial operational modeling system, to be run at NOAA's National Center for Environmental Prediction (NCEP), will consist of NOAA's Eta meteorological model, linked with EPA's Community Multiscale Air Quality (CMAQ) model. The coupled system will produce hourly forecasts of ozone and other photooxidants on a three-dimensional model grid of application covering the eastern U.S. with a grid resolution of 12 km. Hourly meteorological data will be provided by the Eta model to the CMAQ model. In addition, source emissions data from EPA's national inventory and ozone air quality data from EPA's AIRNow database will be provided to the modeling system on an hourly basis. Model guidance will be availalble to local forecasters by early afternoon to make the air quality forecast for the following day. Over the next five years the model domain will be extended to cover the entire continental U.S. and model capability will be extended to provide forecast guidance on fine particulate matter.