title: [Environmental PM2.5 levels and distance from a heavy traffic road in Ciudad Juarez, Chihuahua, Mexico].
abstract: OBJECTIVE
  To assess PM2.5 levels at different distances from a heavy traffic road.
  
  
  METHODS
  Daily measurements of PM2.5 were taken between August 26 and 30, 2002, at different distances from Tecnológico Avenue in Ciudad Juarez, Chihuahua, Mexico. Data analysis consisted of descriptive statistics for each distance and KruskalWallis and cross trend for ranks.
  
  
  RESULTS
  We found a significantly decreasing trend of PM2.5 median levels with increasing distance from Tecnológico Avenue (p<0.001). At 100 m distance from the avenue, PM2.5 levels decreased by 9.5 microg/m3 (40.6%) when compared to median levels registered on the avenue. The results showed a highly significant negative correlation between PM2.5 measurements and the distance from the avenue (r=-0.70, n=20 and p=0.0005).
  
  
  CONCLUSIONS
  PM2.5 median levels decreased significantly after 100 meters from heavy traffic roads. These results are of great relevance when assessing exposure to PM2.5 in epidemiological studies.
authors.affiliation: Centro de Investigación en Salud Poblacional, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México.
authors.forename: Marlene
authors.initials: M
authors.lastname: Cortez-Lugo
authors.forename: Fernando
authors.initials: F
authors.lastname: Holguín-Molina
authors.forename: Silvia
authors.initials: S
authors.lastname: Flores-Luévano
authors.forename: Isabelle
authors.initials: I
authors.lastname: Romieu
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis*; D002947:Cities; D004781:Environmental Exposure / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D016021:Epidemiologic Studies; D062665:Epidemiological Monitoring; D006801:Humans; D008800:Mexico / Q000453:epidemiology; D018986:Motor Vehicles; D010316:Particle Size; D014504:Urban Health / Q000706:statistics & numerical data; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions