title: Application of the tracer-aerosol gradient interpretive technique to sulfur attribution for the big bend regional aerosol and visibility observational study.
abstract: A simple data analysis method called the Tracer-Aerosol Gradient Interpretive Technique (TAGIT) is used to attribute particulate S and SO2 at Big Bend National Park in Texas and nearby areas to local and regional sources. Particulate S at Big Bend is of concern because of its effects on atmospheric visibility. The analysis used particulate S, SO2, and perfluorocarbon tracer data from six 6-hr sampling sites in and near Big Bend National Park. The data were collected in support of the Big Bend Regional Aerosol and Visibility Observational (BRAVO) Study; the field portion was conducted from July through October 1999. Perfluorocarbon tracer was released continuously from a tower at Eagle Pass, TX, approximately 25 km northeast of two large coal-fired power plants (Carbon I and II) in Coahuila, Mexico, and approximately 270 km east-southeast of Big Bend National Park. The perfluorocarbon tracer did not properly represent the location of the emissions from the Carbon power plants for individual 6-hr sampling periods and attributed only 3% of the particulate S and 27% of the SO2 at the 6-hr sites in and near Big Bend to sources represented by the tracer. An alternative approach using SO2 to tag "local" sources such as the Carbon plants attributed 10% of the particulate S and 75% of the SO2 at the 6-hr sites to local sources. Based on these two approaches, most of the regional (65-86%) and a small fraction (19-31%) of the local SO2 was converted to particulate S. The analysis implies that substantial reductions in particulate S at Big Bend National Park cannot be achieved by only reducing emissions from the Carbon power plants; reduction of emissions from many sources over a regional area would be necessary.
authors.affiliation: Division of Atmospheric Science, Desert Research Institute, Las Vegas, Nevada 89119, USA. green@dri.edu
authors.forename: Mark
authors.initials: M
authors.lastname: Green
authors.forename: Hampden
authors.initials: H
authors.lastname: Kuhns
authors.forename: Marc
authors.initials: M
authors.lastname: Pitchford
authors.forename: Russell
authors.initials: R
authors.lastname: Dietz
authors.forename: Lowell
authors.initials: L
authors.lastname: Ashbaugh
authors.forename: Tom
authors.initials: T
authors.lastname: Watson
mesh_terms: D000336:Aerosols / Q000032:analysis; D000393:Air Pollutants / Q000032:analysis*; D003031:Coal; D004784:Environmental Monitoring; D008800:Mexico; D010316:Particle Size; D011210:Power Plants; D013458:Sulfur Dioxide / Q000032:analysis*; D013781:Texas
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D003031:Coal; D013458:Sulfur Dioxide