title: Characterizing spatial patterns of airborne coarse particulate (PM10-2.5) mass and chemical components in three cities: the multi-ethnic study of atherosclerosis.
abstract: BACKGROUND
  The long-term health effects of coarse particular matter (PM10-2.5) are challenging to assess because of a limited understanding of the spatial variation in PM10-2.5 mass and its chemical components.
  
  
  OBJECTIVE
  We conducted a spatially intensive field study and developed spatial prediction models for PM10-2.5 mass and four selected species (copper, zinc, phosphorus, and silicon) in three American cities.
  
  
  METHODS
  PM10-2.5 snapshot campaigns were conducted in Chicago, Illinois; St. Paul, Minnesota; and Winston-Salem, North Carolina, in 2009 for the Multi-Ethnic Study of Atherosclerosis and Coarse Airborne Particulate Matter (MESA Coarse). In each city, samples were collected simultaneously outside the homes of approximately 40 participants over 2 weeks in the winter and/or summer. City-specific and combined prediction models were developed using land use regression (LUR) and universal kriging (UK). Model performance was evaluated by cross-validation (CV).
  
  
  RESULTS
  PM10-2.5 mass and species varied within and between cities in a manner that was predictable by geographic covariates. City-specific LUR models generally performed well for total mass (CV R2, 0.41-0.68), copper (CV R2, 0.51-0.86), phosphorus (CV R2, 0.50-0.76), silicon (CV R2, 0.48-0.93), and zinc (CV R2, 0.36-0.73). Models pooled across all cities inconsistently captured within-city variability. Little difference was observed between the performance of LUR and UK models in predicting concentrations.
  
  
  CONCLUSIONS
  Characterization of fine-scale spatial variability of these often heterogeneous pollutants using geographic covariates should reduce exposure misclassification and increase the power of epidemiological studies investigating the long-term health impacts of PM10-2.5.
authors.affiliation: Division of Epidemiology, Human Genetics and Environmental Sciences, University of Texas School of Public Health, Houston, Texas, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Timothy V
authors.initials: TV
authors.lastname: Larson
authors.forename: Amanda
authors.initials: A
authors.lastname: Gassett
authors.forename: Adam A
authors.initials: AA
authors.lastname: Szpiro
authors.forename: Martha
authors.initials: M
authors.lastname: Daviglus
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Burke
authors.forename: Joel D
authors.initials: JD
authors.lastname: Kaufman
authors.forename: Sara D
authors.initials: SD
authors.lastname: Adar
mesh_terms: D000397:Air Pollution / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D052638:Particulate Matter / Q000032:analysis*
chemical_list: D052638:Particulate Matter