title: The effects of particulate matter sources on daily mortality: a case-crossover study of Barcelona, Spain.
abstract: BACKGROUND
  Dozens of studies link acute exposure to particulate matter (PM) air pollution with premature mortality and morbidity, but questions remain about which species and sources in the vast PM mixture are responsible for the observed health effects. Although a few studies exist on the effects of species and sources in U.S. cities, European cities-which have a higher proportion of diesel engines and denser urban populations-have not been well characterized. Information on the effects of specific sources could aid in targeting pollution control and in articulating the biological mechanisms of PM.
  
  
  OBJECTIVE
  Our study examined the effects of various PM sources on daily mortality for 2003 through 2007 in Barcelona, a densely populated city in the northeast corner of Spain.
  
  
  METHODS
  Source apportionment for PM ≤ 2.5 μm and ≤ 10 µm in aerodynamic diameter (PM2.5 and PM10) using positive matrix factorization identified eight different factors. Case-crossover regression analysis was used to estimate the effects of each factor.
  
  
  RESULTS
  Several sources of PM2.5, including vehicle exhaust, fuel oil combustion, secondary nitrate/organics, minerals, secondary sulfate/organics, and road dust, had statistically significant associations (p < 0.05) with all-cause and cardiovascular mortality. Also, in some cases relative risks for a respective interquartile range increase in concentration were higher for specific sources than for total PM2.5 mass.
  
  
  CONCLUSIONS
  These results along with those from our multisource models suggest that traffic, sulfate from shipping and long-range transport, and construction dust are important contributors to the adverse health effects linked to PM.
authors.affiliation: Centre for Research in Environmental Epidemiology, Barcelona, Spain. Bostro@creal.cat
authors.forename: Bart
authors.initials: B
authors.lastname: Ostro
authors.forename: Aurelio
authors.initials: A
authors.lastname: Tobias
authors.forename: Xavier
authors.initials: X
authors.lastname: Querol
authors.forename: Andrés
authors.initials: A
authors.lastname: Alastuey
authors.forename: Fulvio
authors.initials: F
authors.lastname: Amato
authors.forename: Jorge
authors.initials: J
authors.lastname: Pey
authors.forename: Noemí
authors.initials: N
authors.lastname: Pérez
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
mesh_terms: D002318:Cardiovascular Diseases / Q000401:mortality*; D002947:Cities; D003252:Construction Materials / Q000633:toxicity; D018592:Cross-Over Studies; D004391:Dust / Q000032:analysis; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006801:Humans; D008962:Models, Theoretical; D009026:Mortality; D010316:Particle Size; D052638:Particulate Matter / Q000633:toxicity*; D012044:Regression Analysis; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D001335:Vehicle Emissions / Q000633:toxicity
chemical_list: D004391:Dust; D052638:Particulate Matter; D001335:Vehicle Emissions