title: Source apportionment of Phoenix PM2.5 aerosol with the Unmix receptor model.
abstract: The multivariate receptor model Unmix has been used to analyze a 3-yr PM2.5 ambient aerosol data set collected in Phoenix, AZ, beginning in 1995. The analysis generated source profiles and overall average percentage source contribution estimates (SCEs) for five source categories:gasoline engines (33 +/- 4%), diesel engines (16 +/- 2%), secondary SO4(2-) (19 +/- 2%), crustal/soil (22 +/- 2%), and vegetative burning (10 +/- 2%). The Unmix analysis was supplemented with scanning electron microscopy (SEM) of a limited number of filter samples for information on possible additional low-strength sources. Except for the diesel engine source category, the Unmix SCEs were generally consistent with an earlier multivariate receptor analysis of essentially the same data using the Positive Matrix Factorization (PMF) model. This article provides the first demonstration for an urban area of the capability of the Unmix receptor model.
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA. lewis.charlesw@epa.gov
authors.forename: Charles W
authors.initials: CW
authors.lastname: Lewis
authors.forename: Gary A
authors.initials: GA
authors.lastname: Norris
authors.forename: Teri L
authors.initials: TL
authors.lastname: Conner
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Henry
mesh_terms: D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D010316:Particle Size; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D001335:Vehicle Emissions