title: Association Between Short-term Exposure to Ultrafine Particles and Mortality in Eight European Urban Areas.
abstract: Epidemiologic evidence on the association between short-term exposure to ultrafine particles and mortality is weak, due to the lack of routine measurements of these particles and standardized multicenter studies. We investigated the relationship between ultrafine particles and particulate matter (PM) and daily mortality in eight European urban areas.
  
  
  
  We collected daily data on nonaccidental and cardiorespiratory mortality, particle number concentrations (as proxy for ultrafine particle number concentration), fine and coarse PM, gases and meteorologic parameters in eight urban areas of Finland, Sweden, Denmark, Germany, Italy, Spain, and Greece, between 1999 and 2013. We applied city-specific time-series Poisson regression models and pooled them with random-effects meta-analysis.
  
  
  
  We estimated a weak, delayed association between particle number concentration and nonaccidental mortality, with mortality increasing by approximately 0.35% per 10,000 particles/cm increases in particle number concentration occurring 5 to 7 days before death. A similar pattern was found for cause-specific mortality. Estimates decreased after adjustment for fine particles (PM2.5) or nitrogen dioxide (NO2). The stronger association found between particle number concentration and mortality in the warmer season (1.14% increase) became null after adjustment for other pollutants.
  
  
  
  We found weak evidence of an association between daily ultrafine particles and mortality. Further studies are required with standardized protocols for ultrafine particle data collection in multiple European cities over extended study periods.
authors.affiliation: From the aDepartment of Epidemiology, Lazio Region Health Service, Rome, Italy; bInstitute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; cHelmholtz Zentrum München-German Research Center for Environmental Health, Institute of Epidemiology II, Neuherberg, Germany; dUniversity of Augsburg, Environmental Science Center, Augsburg, Germany; eDepartment of Hygiene, Epidemiology and Medical Statistics, National and Kapodistrian University of Athens, Athens, Greece; fDepartment of Public Health, Center for Epidemiology and Screening, University of Copenhagen, Copenhagen, Denmark; gStockholm County Council, Centre for Occupational and Environmental Medicine, Stockholm, Sweden; hItalian National Institute for Environmental Protection and Research, Rome, Italy; iNCSR Demokritos, Institute of Nuclear and Radiological Sciences & Technology, Energy and Safety, Environmental Radioactivity Laboratory, Athens, Greece; jIUF-Leibniz Research Institute for Environmental Medicine at the University of Düsseldorf, Düsseldorf, Germany; kMedical Faculty, University of Düsseldorf, Düsseldorf, Germany; lINSERM-Aging and Chronic Diseases, Epidemiological and Public Health Approaches (VIMA), Villejuif, France; mBarcelona Institute for Global Health - Campus MAR (ISGlobal), Barcelona, Spain; nDepartment of Environmental Science, Faculty of Science and Technology, Aarhus University, Roskilde, Copenhagen; oDepartment of Public Health, University of Helsinki, Helsinki, Finland; pDepartment of Health Protection, Living Environment and Health Unit, National Institute for Health and Welfare (THL), Kuopio, Finland; qInstitute of Environmental Assessment and Water Research, Barcelona, Spain; and rInstitute for Energy and Environmental Technology IUTA e.V., Air Quality & Sustainable Nanotechnology Unit, Duisburg, Germany.
authors.forename: Massimo
authors.initials: M
authors.lastname: Stafoggia
authors.forename: Alexandra
authors.initials: A
authors.lastname: Schneider
authors.forename: Josef
authors.initials: J
authors.lastname: Cyrys
authors.forename: Evangelia
authors.initials: E
authors.lastname: Samoli
authors.forename: Zorana Jovanovic
authors.initials: ZJ
authors.lastname: Andersen
authors.forename: Getahun Bero
authors.initials: GB
authors.lastname: Bedada
authors.forename: Tom
authors.initials: T
authors.lastname: Bellander
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cattani
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Eleftheriadis
authors.forename: Annunziata
authors.initials: A
authors.lastname: Faustini
authors.forename: Barbara
authors.initials: B
authors.lastname: Hoffmann
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Jacquemin
authors.forename: Klea
authors.initials: K
authors.lastname: Katsouyanni
authors.forename: Andreas
authors.initials: A
authors.lastname: Massling
authors.forename: Juha
authors.initials: J
authors.lastname: Pekkanen
authors.forename: Noemi
authors.initials: N
authors.lastname: Perez
authors.forename: Annette
authors.initials: A
authors.lastname: Peters
authors.forename: Ulrich
authors.initials: U
authors.lastname: Quass
authors.forename: Tarja
authors.initials: T
authors.lastname: Yli-Tuomi
authors.forename: Francesco
authors.initials: F
authors.lastname: Forastiere
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000397:Air Pollution / Q000706:statistics & numerical data*; D002648:Child; D002675:Child, Preschool; D002947:Cities; D003718:Denmark; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005060:Europe; D005260:Female; D005387:Finland; D005858:Germany; D006115:Greece; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007558:Italy; D008297:Male; D008875:Middle Aged; D009026:Mortality; D009585:Nitrogen Dioxide; D052638:Particulate Matter; D016012:Poisson Distribution; D012044:Regression Analysis; D013030:Spain; D013548:Sweden; D013997:Time Factors; D014505:Urban Population / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D052638:Particulate Matter; D009585:Nitrogen Dioxide