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NARSTO Workshop on Innovative Methods for Emission Inventory Development and Evaluation University of Texas, Austin October 14-17, 2003 |
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Estimation of Mobile Emission Ratios for Sulfur, Nitrogen, Carbon and Mercury from Field Measurements in Atlanta, GA
Eric S. Edgerton
Atmospheric Res. & Analysis, Inc., Cary, NC
John J. Jansen
Southern Company, Birmingham, AL
This presentation uses high temporal resolution gas and particle data from a site in Atlanta, GA to estimate mobile emission ratios for a variety of gaseous species (including NOx, SO2 and elemental Hg) and particulate species (including PM2.5 mass, elemental carbon and total carbon). Data are analyzed for the Jefferson Street SEARCH site, where a wide variety of gas, particle and meteorological measurements have been made with 1-minute to 60-minute time resolution since August 1998. The analysis approach focuses on covariance of target species with CO during periods of nocturnal stagnation. Under these conditions, locally emitted pollutants increase significantly under the nocturnal boundary layer. Linear regression analysis is used to extract the emission ratio of interest (i.e., relative to CO). Emission ratios will be presented for a number of what appear to be purely gasoline and diesel events. Results for the 4-year period 1998-2002 will be presented for NOx:CO, PM2.5:CO and EC:CO. Year to year variability will be assessed. Data for a shorter period of record (i.e., 2002) will be used to estimate elemental Hg:CO emission ratios. Results will be compared with expected ratios based on emission inventories and the literature.