title: Constrained Source Apportionment of Coarse Particulate Matter and Selected Trace Elements in Three Cities from the Multi-Ethnic Study of Atherosclerosis.
abstract: PM10-2.5mass and trace element concentrations were measured in Winston-Salem, Chicago, and St. Paul at up to 60 sites per city during two different seasons in 2010. Positive Matrix Factorization (PMF) was used to explore the underlying sources of variability. Information on previously reported PM10-2.5tire and brake wear profiles was used to constrain these features in PMF by prior specification of selected species ratios. We also modified PMF to allow for combining the measurements from all three cities into a single model while preserving city-specific soil features. Relatively minor differences were observed between model predictions with and without the prior ratio constraints, increasing confidence in our ability to identify separate brake wear and tire wear features. Brake wear, tire wear, fertilized soil, and re-suspended soil were found to be important sources of copper, zinc, phosphorus, and silicon respectively across all three urban areas.
authors.affiliation: Department of Civil & Environmental Engineering University of Washington, Box 352700, Seattle, WA 98195-2700., USA.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Sturtz
authors.affiliation: Department of Epidemiology, School of Public Health University of Michigan, 1415 Washington Heights, Ann Arbor, MI, 48109-2029, USA; Department of Environmental & Occupational Health Sciences University of Washington, Box 357234, Seattle, WA 98195-7234, USA.
authors.forename: Sara D
authors.initials: SD
authors.lastname: Adar
authors.affiliation: Department of Civil & Environmental Engineering University of Washington, Box 352700, Seattle, WA 98195-2700., USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Gould
authors.affiliation: Department of Civil & Environmental Engineering University of Washington, Box 352700, Seattle, WA 98195-2700., USA; Department of Environmental & Occupational Health Sciences University of Washington, Box 357234, Seattle, WA 98195-7234, USA.
authors.forename: Timothy V
authors.initials: TV
authors.lastname: Larson
keywords: agriculture; air pollution; brake wear; coarse particulate matter; positive matrix factorization; soil; source apportionment; tire wear; trace elements