title: Urban air pollution, and asthma and COPD hospital emergency room visits.
abstract: BACKGROUND
  There is little previous information of the effects of size fractioned particulate air pollution and source specific fine particles (PM(2.5); <2.5 microm) on asthma and chronic obstructive pulmonary disease (COPD) among children, adults and the elderly.
  
  
  OBJECTIVE
  To determine the effects of daily variation in levels of different particle size fractions and gaseous pollutants on asthma and COPD by age group.
  
  
  METHODS
  Levels of particulate air pollution, NO(2) and CO were measured from 1998 to 2004 at central outdoor monitoring sites in Helsinki, Finland. Associations between daily pollution levels and hospital emergency room visits were evaluated for asthma (ICD10: J45+J46) in children <15 years old, and for asthma and COPD (ICD10: J41+J44) in adults (15-64 years) and the elderly (>or=65 years).
  
  
  RESULTS
  Three to 5 day lagged increases in asthma visits were found among children in association with nucleation (<0.03 microm), Aitken (0.03-0.1 microm) and accumulation (0.1-0.29 microm) mode particles, gaseous pollutants and traffic related PM(2.5) (7.8% (95% CI 3.5 to 12.3) for 1.1 microg/m(3) increase in traffic related PM(2.5) at lag 4). Pooled asthma-COPD visits among the elderly were associated with lag 0 of PM(2.5), coarse particles, gaseous pollutants and long range transported and traffic related PM(2.5) (3.9% (95% CI 0.28 to 7.7) at lag 0). Only accumulation mode and coarse particles were associated with asthma and COPD among adults.
  
  
  CONCLUSIONS
  Among children, traffic related PM(2.5) had delayed effects, whereas among the elderly, several types of particles had effects that were more immediate. These findings suggest that the mechanisms of the respiratory effects of air pollution, and responsible pollutants, differ by age group.
authors.affiliation: National Public Health Institute (KTL), Environmental Epidemiology Unit, PO Box 95, FIN-70701 Kuopio, Finland. jaana.halonen@ktl.fi
authors.forename: J I
authors.initials: JI
authors.lastname: Halonen
authors.forename: T
authors.initials: T
authors.lastname: Lanki
authors.forename: T
authors.initials: T
authors.lastname: Yli-Tuomi
authors.forename: M
authors.initials: M
authors.lastname: Kulmala
authors.forename: P
authors.initials: P
authors.lastname: Tiittanen
authors.forename: J
authors.initials: J
authors.lastname: Pekkanen
mesh_terms: D000293:Adolescent; D000328:Adult; D000397:Air Pollution / Q000009:adverse effects*; D001249:Asthma / Q000139:chemically induced*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005387:Finland; D006801:Humans; D008875:Middle Aged; D052638:Particulate Matter / Q000633:toxicity*; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D029424:Pulmonary Disease, Chronic Obstructive / Q000139:chemically induced*; D014504:Urban Health; D001335:Vehicle Emissions / Q000633:toxicity
chemical_list: D052638:Particulate Matter; D001335:Vehicle Emissions