title: Outdoor particulate matter and childhood asthma admissions in Athens, Greece: a time-series study.
abstract: BACKGROUND
  Particulate matter with diameter less than 10 micrometers (PM10) that originates from anthropogenic activities and natural sources may settle in the bronchi and cause adverse effects possibly via oxidative stress in susceptible individuals, such as asthmatic children. This study aimed to investigate the effect of outdoor PM10 concentrations on childhood asthma admissions (CAA) in Athens, Greece.
  
  
  METHODS
  Daily counts of CAA from the three Children's Hospitals within the greater Athens' area were obtained from the hospital records during a four-year period (2001-2004, n = 3602 children). Mean daily PM10 concentrations recorded by the air pollution-monitoring network of the greater Athens area were also collected. The relationship between CAA and PM10 concentrations was investigated using the Generalized Linear Models with Poisson distribution and logistic analysis.
  
  
  RESULTS
  There was a statistically significant (95% CL) relationship between CAA and mean daily PM10 concentrations on the day of exposure (+3.8% for 10 microg/m3 increase in PM10 concentrations), while a 1-day lag (+3.4% for 10 microg/m3 increase in PM10 concentrations) and a 4-day lag (+4.3% for 10 microg/m3 increase in PM10 concentrations) were observed for older asthmatic children (5-14 year-old). High mean daily PM10 concentration (the highest 10%; >65.69 microg/m3) doubled the risk of asthma exacerbations even in younger asthmatic children (0-4 year-old).
  
  
  CONCLUSIONS
  Our results provide evidence of the adverse effect of PM10 on the rates of paediatric asthma exacerbations and hospital admissions. A four-day lag effect between PM10 peak exposure and asthma admissions was also observed in the older age group.
authors.affiliation: Laboratory of Climatology and Atmospheric Environment, Department of Geology and Geoenvironment, University of Athens, Panepistimioupolis, 157 84 Athens, Greece. nastos@geol.uoa.gr
authors.forename: Panagiotis T
authors.initials: PT
authors.lastname: Nastos
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Paliatsos
authors.forename: Michael B
authors.initials: MB
authors.lastname: Anthracopoulos
authors.forename: Eleftheria S
authors.initials: ES
authors.lastname: Roma
authors.forename: Kostas N
authors.initials: KN
authors.lastname: Priftis
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000009:adverse effects*; D001249:Asthma / Q000139:chemically induced / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D006115:Greece / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D052638:Particulate Matter; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter