title: Characterization of PM25and PM10in the South Coast Air Basin of Southern California: Part 1-Spatial Variations.
abstract: In December 1994, the South Coast Air Quality Management District (SCAQMD) initiated a comprehensive program, the PM10Technical Enhancement Program (PTEP), to characterize fine PM in the South Coast Air Basin (SCAB). A 1-year special particulate monitoring project was conducted from January 1995 to February 1996 as part of the PTEP. Under this enhanced monitoring, HNO3, NH3, and speciated PM10and PM2.5concentrations were measured at five stations (Anaheim, downtown Los Angeles, Diamond Bar, Fontana, and Rubidoux) in the SCAB and at one background station at San Nicolas Island. PM2.5and PM10mass and 43 individual species were analyzed for a full chemical speciation of the particle data. The PTEP data indicate that the most abundant chemical components of PM10and PM25in the SCAB are NH4+ (8-9% of PM10and 14-17% of PM25), NO3-(23-26% of PM10and 28-41% of PM25), SO4= (6-11% of PM10and 9-18% of PM2 5), organic carbon (OC) (15-19% of PM10and 18-26% of PM2.5), and elemental carbon (EC) (5-8% of PM10and 8-13% of PM25). On an annual average basis, PM25comprises 52-59% of the SCAB PM10. Annual average PM10and PM2.5concentrations showed strong spatial variations, low at coastal sites and high at inland sites. Annual average PM10concentrations varied from 40.8 ug/m3at Anaheim to 76.8 ug/m3at Rubidoux, while annual average PM2.5concentrations varied from 21.7 ug/m3at Anaheim to 39.8 ug/m3at Rubidoux. The chemical characterizations of the PM2.5and PM10concentrations, as well as their spatial variations, were examined; the important findings are summarized in this paper, and the temporal variations are discussed in the companion paper.1.
authors.affiliation: a South Coast Air Quality Management District, Planning and Policy , Diamond Bar , California , USA.
authors.forename: Bong Mann
authors.initials: BM
authors.lastname: Kim
authors.affiliation: a South Coast Air Quality Management District, Planning and Policy , Diamond Bar , California , USA.
authors.forename: Solomon
authors.initials: S
authors.lastname: Teffera
authors.affiliation: a South Coast Air Quality Management District, Planning and Policy , Diamond Bar , California , USA.
authors.forename: Melvin D
authors.initials: MD
authors.lastname: Zeldin