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A REGIONAL ATMOSPHERIC FATE AND TRANSPORT MODEL FOR ATRAZINE PART II: EVALUATION
Citation:
Cooter, E J., W T. Hutzell, W. T. Foreman, AND M. S. Majewski. A REGIONAL ATMOSPHERIC FATE AND TRANSPORT MODEL FOR ATRAZINE PART II: EVALUATION. ENVIRONMENTAL SCIENCE & TECHNOLOGY 36(21):4593-4599, (2002).
Impact/Purpose:
The goal of this research is to develop and test appropriate chemical and physical mechanisms for use in EPA's Models-3 chemical/transport models. These models will be addressing issues of tropospheric photochemistry, fine particles, toxic and semi-volatile substances, and acid deposition. As such, scientifically credible mechanisms for atmospheric gas- and aqueous-phase chemistry as well as heterogeneous chemistry, applicable to the particular pollutant regimes must be included in Models-3.
Description:
The Community Multiscale Air Quality (CMAQ) modeling system has been adapted to simulate the fate and transport of atrazine. The simulation spans April to mid-July 1995 for a domain encompassing the United States and southern Canada east of the Rocky Mountains. Model results for atmospheric concentration and wet deposition are evaluated against field observations taken along the Mississippi River and the shores of Lake Michigan. Model results agree within 10% of published annual atmospheric load estimates for Lake Michigan during 1995, but comparisons with individual 7- and 30-day observed air and rainfall concentrations yield order-of-magnitude differences. In particular, ambient gas-phase concentrations tend to be overpredicted by the model. Uncertainty in short-term predictions of air and rainfall concentrations appear to derive primarily from estimated emissions and precipitation.