title: Size distribution and total number concentration of ultrafine and accumulation mode particles and hospital admissions in children and the elderly in Copenhagen, Denmark.
abstract: OBJECTIVE
  To study the association between short-term exposure to ultrafine particles and morbidity in Copenhagen, Denmark.
  
  
  METHODS
  We studied the association between urban background levels of the total number concentration of particles (NC(tot), 6-700 nm in diameter) measured at a single site (15 May 2001 to 31 December 2004) and hospital admissions due to cardiovascular (CVD) and respiratory disease (RD) in the elderly (age >or=65 years), and due to asthma in children (age 5-18 years). We examined these associations in the presence of PM(10), PM(2.5) (particulate matter <10 and 2.5 microm in diameter, respectively) and ambient gasses. We utilised data on size distribution to calculate NC(tot) for four modes with median diameters 12, 23, 57 and 212 nm, and NC(100) (number concentration of particles <100 nm in diameter) and examined their associations with health outcomes. We used a time series Poisson generalised additive model adjusted for overdispersion, season, day of the week, public holidays, school holidays, influenza, pollen and meteorology, with up to 5 days' lagged exposure.
  
  
  CONCLUSIONS
  The adverse health effects of particulate matter on CVD and RD hospital admissions in the elderly were mainly mediated by PM(10) and accumulation mode particles with lack of effects for NC(100). For paediatric asthma, accumulation mode particles, NC(100) and nitrogen oxides (mainly from traffic related sources) were relevant, whereas PM(10) appeared to have little effect. Our results suggest that particle volume/mass from long-range transported air pollution is relevant for CVD and RD admissions in the elderly, and possibly particle numbers from traffic sources for paediatric asthma.
authors.affiliation: Department of Biostatistics, Institute of Public Health, Copenhagen University, Øster Farimagsgade, 5 Entr. B, PO Box 2099, 1014 Copenhagen K, Denmark. zorana@cancer.dk
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Andersen
authors.forename: P
authors.initials: P
authors.lastname: Wahlin
authors.forename: O
authors.initials: O
authors.lastname: Raaschou-Nielsen
authors.forename: M
authors.initials: M
authors.lastname: Ketzel
authors.forename: T
authors.initials: T
authors.lastname: Scheike
authors.forename: S
authors.initials: S
authors.lastname: Loft
mesh_terms: D000293:Adolescent; D000368:Aged; D000393:Air Pollutants / Q000633:toxicity*; D001249:Asthma / Q000209:etiology*; D002318:Cardiovascular Diseases / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D003718:Denmark; D004391:Dust; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D019570:Inhalation Exposure; D009589:Nitrogen Oxides / Q000633:toxicity; D010316:Particle Size; D014504:Urban Health; D014887:Weather
chemical_list: D000393:Air Pollutants; D004391:Dust; D009589:Nitrogen Oxides