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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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Real-Time Monitoring of Gases and Aerosols Reveals Source Contributions to Air Quality
N. Poor, C. Amalfitano
Environmental and Occupational Health, College of Public Health
University of South Florida, Tampa, FL 33612
J. M. Ondov, P. Pancras, and S. Gazula
Department of Chemistry and Biochemistry
University of Maryland, College Park, MD 20742
P. Dasgupta, R. Al-Horr
Department of Chemistry and Biochemistry
Texas Tech University, Lubbock, TX 79409
In May 2002, the Bay Regional Atmospheric Chemistry Experiment (BRACE) held a month-long intensive monitoring campaign with ambient air quality measurements made at 5 sites within ~20 km of Tampa Bay. The objectives of the BRACE were to improve estimates of the atmospheric nitrogen deposition, to apportion the atmospheric nitrogen to among its contributing sources, and to assess the Tampa Bay air quality before and after the re-powering of a major coal-fired utility. At one rural site to the east of Tampa were deployed a differential optical absorption spectrophotometer (DOAS), a semi-continuous elements in aerosol sampler (SEAS), and a semi-continuous acidic and basic gas and aerosol sampler based on ion chromatography (IC). With the DOAS were measured at minute resolution sulfur dioxide, nitrogen dioxide, ozone, and o-xylene; at a 30-min resolution the SEAS captured 12 discernible elements useful as markers of primary particle emissions for high-temperature combustion sources; the IC had 15-min resolution of sulfur dioxide, nitric acid, nitrous acid, hydrochloric acid, oxalic acid and ammonia; and sulfate, nitrate, nitrite, chloride, oxalate and ammonium. This combination and temporal resolution of gases and aerosol samples reveals interesting relationships strongly suggestive of known regional nitrogen sources, for example, fertilizer manufacturing and coal combustion, and offers the opportunity to assess inventories by comparing predicted with measured species ratios over a wider range of chemical species.