title: Effects of long-range transported air pollution from vegetation fires on daily mortality and hospital admissions in the Helsinki metropolitan area, Finland.
abstract: BACKGROUND
  Fine particulate matter (PM2.5) emissions from vegetation fires can be transported over long distances and may cause significant air pollution episodes far from the fires. However, epidemiological evidence on health effects of vegetation-fire originated air pollution is limited, particularly for mortality and cardiovascular outcomes.
  
  
  OBJECTIVE
  We examined association between short-term exposure to long-range transported PM2.5from vegetation fires and daily mortality due to non-accidental, cardiovascular, and respiratory causes and daily hospital admissions due to cardiovascular and respiratory causes in the Helsinki metropolitan area, Finland.
  
  
  METHODS
  Days significantly affected by smoke from vegetation fires between 2001 and 2010 were identified using air quality measurements at an urban background and a regional background monitoring station, and modelled data on surface concentrations of vegetation-fire smoke. Associations between daily PM2.5concentration and health outcomes on i) smoke-affected days and ii) all other days (i.e. non-smoke days) were analysed using Poisson time series regression. All statistical models were adjusted for daily temperature and relative humidity, influenza, pollen, and public holidays.
  
  
  RESULTS
  On smoke-affected days, 10µg/m3increase in PM2.5was associated with a borderline statistically significant increase in cardiovascular mortality among total population at a lag of three days (12.4%, 95% CI -0.2% to 26.5%), and among the elderly (≥65 years) following same-day exposure (13.8%, 95% CI -0.6% to 30.4%) and at a lag of three days (11.8%, 95% CI -2.2% to 27.7%). Smoke day PM2.5was not associated with non-accidental mortality or hospital admissions due to cardiovascular causes. However, there was an indication of a positive association with hospital admissions due to respiratory causes among the elderly, and admissions due to chronic obstructive pulmonary disease or asthma among the total population. In contrast, on non-smoke days PM2.5was generally not associated with the health outcomes, apart from suggestive small positive effects on non-accidental mortality at a lag of one day among the elderly and hospital admissions due to all respiratory causes following same-day exposure among the total population.
  
  
  CONCLUSIONS
  Our research provides suggestive evidence for an association of exposure to long-range transported PM2.5from vegetation fires with increased cardiovascular mortality, and to a lesser extent with increased hospital admissions due to respiratory causes. Hence, vegetation-fire originated air pollution may have adverse effects on public health over a distance of hundreds to thousands of kilometres from the fires.
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, P.O. Box 95, FI-70701 Kuopio, Finland. Electronic address: virpi.kollanus@thl.fi.
authors.forename: Virpi
authors.initials: V
authors.lastname: Kollanus
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, P.O. Box 95, FI-70701 Kuopio, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Tiittanen
authors.affiliation: Helsinki Region Environmental Services Authority, P.O. Box 100, FI-00066 HSY, Helsinki, Finland; Department of Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014 University of Helsinki, Helsinki, Finland.
authors.forename: Jarkko V
authors.initials: JV
authors.lastname: Niemi
authors.affiliation: Department of Health Protection, National Institute for Health and Welfare, P.O. Box 95, FI-70701 Kuopio, Finland; Unit of Public Health and Clinical Nutrition, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Lanki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution / Q000009:adverse effects*; D002318:Cardiovascular Diseases / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009026:Mortality; D010343:Patient Admission / Q000706:statistics & numerical data*; D012906:Smoke / Q000009:adverse effects*; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D012906:Smoke
keywords: Air pollution; Hospital admissions; Mortality; Particulate matter; Vegetation fire