APPORTIONMENT OF SULFUR-OXIDES AT CANYONLANDS DURING THE WINTER OF 1990 .1. STUDY DESIGN AND PARTICULATE CHEMICAL-COMPOSITION

Spherical aluminosilicate (SAS) particles, total fluoride and particul ate trace elements are potential endemic tracers for determining and q uantifying the presence of coal-fired power plant and other sulfur oxi de source emissions at far downwind distances. These endemic tracers, and sulfate and SO, were collected at Canyonlands National Park, at se ven ambient sampling sites located in air mass transport paths to Cany onlands and from the stacks of coal-fired power plants in central Utah during January-March of 1990 for use in source apportionment analyses . These data have been combined with results obtained in concurrent st udies by the National Park Service (EPIC study) and Salt River Project to provide a complete data set for the characterization of the region al and point sources that can influence gir quality in the Canyonlands area, This paper gives details on the study design and on the chemica l composition of fine particulate matter in the study area. While conc entrations of SOx(SO2(g) plus particulate sulfate) were in good agreem ent among the various studies, accurate concentrations for sulfate and SO2 were only obtained using a diffusion denuder sampling system beca use of the absorption of SO2(g) by particles in all filter pack sampli ng systems. Concentrations of F-Total (HF(g) plus particulate fluoride ), and particulate Se, As, and Pb determined by multiple techniques we re generally in good agreement. Sulfate (assumed present as ammonium s ulfate) and nitrate (assumed present as ammonium nitrate) accounted fo r an average of 19 and 4%, respectively, of the fine particulate mass collected at Canyonlands and 8 and 2% of the fine particulate mass at Green River, Utah. Data were available at the Edge of the Cedars, Utah , sampling site to estimate the complete chemical composition of the f ine particles. The average concentration of fine particles at Edge of the Cedars was 15 mu g m(-3). Sulfate (as the ammonium salt) averaged 15% of the fine particulate mass, comparable to Canyonlands. Nonsulfat e inorganic compounds averaged 58% of the mass. The majority of these inorganic species are background desert particles. The remainder of th e mass, 27%, is presumably water, and organic and elemental carbon.