title: Time-series analysis of mortality effects of fine particulate matter components in Detroit and Seattle.
abstract: BACKGROUND
  Recent toxicological and epidemiological studies have shown associations between particulate matter (PM) and adverse health effects, but which PM components are most influential is less well known.
  
  
  OBJECTIVE
  In this study, we used time-series analyses to determine the associations between daily fine PM [PM ≤ 2.5 µm in aerodynamic diameter (PM2.5)] concentrations and daily mortality in two U.S. cities-Seattle, Washington, and Detroit, Michigan.
  
  
  METHODS
  We obtained daily PM2.5 filters for the years of 2002-2004 and analyzed trace elements using X-ray fluorescence and black carbon using light reflectance as a surrogate measure of elemental carbon. We used Poisson regression and distributed lag models to estimate excess deaths for all causes and for cardiovascular and respiratory diseases adjusting for time-varying covariates. We computed the excess risks for interquartile range increases of each pollutant at lags of 0 through 3 days for both warm and cold seasons.
  
  
  RESULTS
  The cardiovascular and respiratory mortality series exhibited different source and seasonal patterns in each city. The PM2.5 components and gaseous pollutants associated with mortality in Detroit were most associated with warm season secondary aerosols and traffic markers. In Seattle, the component species most closely associated with mortality included those for cold season traffic and other combustion sources, such as residual oil and wood burning.
  
  
  CONCLUSIONS
  The effects of PM2.5 on daily mortality vary with source, season, and locale, consistent with the hypothesis that PM composition has an appreciable influence on the health effects attributable to PM.
authors.affiliation: New York University School of Medicine, Tuxedo, New York 10987, USA. jz603@nyu.edu
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhou
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ito
authors.forename: Ramona
authors.initials: R
authors.lastname: Lall
authors.forename: Morton
authors.initials: M
authors.lastname: Lippmann
authors.forename: George
authors.initials: G
authors.lastname: Thurston
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D000397:Air Pollution / Q000706:statistics & numerical data*; D002318:Cardiovascular Diseases / Q000401:mortality*; D004781:Environmental Exposure / Q000032:analysis / Q000706:statistics & numerical data; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D006801:Humans; D008824:Michigan / Q000453:epidemiology; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis* / Q000633:toxicity; D012140:Respiratory Tract Diseases / Q000401:mortality*; D014861:Washington / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter