title: The impacts of traffic-related and woodsmoke particulate matter on measures of cardiovascular health: a HEPA filter intervention study.
abstract: BACKGROUND
  Combustion-generated fine particulate matter (PM2.5) is associated with cardiovascular morbidity. Both traffic-related air pollution and residential wood combustion may be important, but few studies have compared their impacts.
  
  
  OBJECTIVE
  To assess and compare effects of traffic-related and woodsmoke PM2.5 on endothelial function and systemic inflammation (C reactive protein, interleukin-6 and band cells) among healthy adults in Vancouver, British Columbia, Canada, using high efficiency particulate air (HEPA) filtration to introduce indoor PM2.5 exposure gradients.
  
  
  METHODS
  We recruited 83 healthy adults from 44 homes in traffic-impacted or woodsmoke-impacted areas to participate in this randomised, single-blind cross-over intervention study. PM2.5 concentrations were measured during two consecutive 7-day periods, one with filtration and the other with 'placebo filtration'. Endothelial function and biomarkers of systematic inflammation were measured at the end of each 7-day period.
  
  
  RESULTS
  HEPA filtration was associated with a 40% decrease in indoor PM2.5 concentrations. There was no relationship between PM2.5 exposure and endothelial function. There was evidence of an association between indoor PM2.5 and C reactive protein among those in traffic-impacted locations (42.1% increase in C reactive protein per IQR increase in indoor PM2.5, 95% CI 1.2% to 99.5%), but not among those in woodsmoke-impacted locations. There were no associations with interleukin-6 or band cells.
  
  
  CONCLUSIONS
  Evidence of an association between C reactive protein and indoor PM2.5 among healthy adults in traffic-impacted areas is consistent with the hypothesis that traffic-related particles, even at relatively low concentrations, play an important role in the cardiovascular effects of the urban PM mixture.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov (NCT01570062).
authors.affiliation: School of Population and Public Health, The University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Majid
authors.initials: M
authors.lastname: Kajbafzadeh
authors.affiliation: School of Population and Public Health, The University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Brauer
authors.affiliation: School of Population and Public Health, The University of British Columbia, Vancouver, British Columbia, Canada Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Barbara
authors.initials: B
authors.lastname: Karlen
authors.affiliation: School of Population and Public Health, The University of British Columbia, Vancouver, British Columbia, Canada Department of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Carlsten
authors.affiliation: Department of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Stephan
authors.initials: S
authors.lastname: van Eeden
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Allen
mesh_terms: D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity; D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000032:analysis / Q000517:prevention & control; D015415:Biomarkers / Q000032:analysis; D001955:British Columbia; D002097:C-Reactive Protein / Q000032:analysis; D002318:Cardiovascular Diseases / Q000209:etiology*; D018592:Cross-Over Studies; D042783:Endothelial Cells; D005260:Female; D005374:Filtration / Q000379:methods; D006801:Humans; D007249:Inflammation / Q000209:etiology; D019570:Inhalation Exposure / Q000009:adverse effects*; D015850:Interleukin-6 / Q000032:analysis; D008297:Male; D008875:Middle Aged; D018986:Motor Vehicles; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D012906:Smoke / Q000009:adverse effects; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity; D014934:Wood; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D015850:Interleukin-6; D052638:Particulate Matter; D012906:Smoke; D001335:Vehicle Emissions; D002097:C-Reactive Protein