The Effect of Feedback Mechanisms and Transport Processes on Oxidants and Aerosols at Multiple Scales

Jerome Fast
Pacific Northwest National Laboratory
P.O. Box 999
Richlandd, WA 99352
509-372-6116
fax 509-372-6188
Jerome.Fast@pnl.gov

L. A. Barrie
Pacific Northwest National Laboratory

In collaboration with government and university researchers in the Atmospheric Chemistry Program (ACP), existing PNNL atmospheric chemistry model components are being integrated into an advanced multi-scale meteorological-chemical-aerosol model. It will be available to ACP scientists to examine a variety of issues associated with oxidant and aerosol chemistry. The model is being used to address three questions of major importance to the ACP mission: (1) how does the interaction of air pollution with radiation and clouds affect ozone and total oxidant production in an urban environment, (2) what is the influence of long-range and regional-scale transport on urban pollutant concentrations in North America, and, (3) as a function of aerosol size, how does aerosol mass and composition in urban areas apportion between long range transport and local production? A combined data analysis and modeling approach is being used to elucidate the feedback mechanisms between air chemistry and meteorology and their effect on oxidant and aerosol distributions. Long-range and regional-scale transport processes are important, because they provide the background chemical environment upon which local emissions are superimposed. Our analysis utilizes previous ACP field campaigns (Phoenix, 1998; Philadelphia, 1999; the Tropospheric Ozone Production about the Spring Equinox experiment, 2000, http://www.pnl.gov/atmos_sciences/topse.html) and two future ACP field campaigns (Houston, 2000; Phoenix, 2001). The data analyses and modeling studies are expected to show that a fully-coupled system is needed to form a complete description of the urban and regional-scale chemical-meteorological environment.

Some further information, on the planned Phoenix 2001 Air Chemistry Study, can be found in the viewgraphs from a presentation at the Atmospheric Sciences Program Annual Meeting held in February 2001. Information on analysis of results from the NEOPS field campaign can be found in the viewgraphs from a presentation at the Atmospheric Sciences Program Annual meeting held in March 2002.