title: Environmental exposure of commuters in Mexico City to volatile organic compounds as assessed by blood concentrations, 1998.
abstract: OBJECTIVE
  To assess the extent of exposure for Volatile Organic Compounds (VOCs) among nonoccupationally exposed commuters in Mexico City.
  
  
  METHODS
  Blood concentrations of benzene, toluene, ethylbenzene, m-/p-xylene, o-xylene and methyl tert-butyl ether were determined on samples collected from participants after the morning commute.
  
  
  RESULTS
  Median blood concentrations of benzene (0.11 microg/l), ethylbenzene (0.081 microg/l), m-/p-xylene (0.32 microg/l) and toluene (0.56 microg/l) in the Mexico City participants were all approximately two times higher than in a nonsmoking subset of the Third National Health and Nutrition Examination Survey population of the United States. On the other hand, median VOC blood levels were similar to medians observed in other studies involving commuters in specific U.S. cities, despite the fact that only half the Mexico City study participants commuted by personal vehicles compared with all U.S. commuters.
  
  
  CONCLUSIONS
  These results reflect the extent of the air pollution problem in Mexico City. The surrounding topography exacerbates the problems caused by heavy vehicular traffic, poor emission-control devices on older vehicles, and poor maintenance practices. Elevated levels of gasoline components in the blood of nonoccupationally exposed commuters emphasize the need for regulatory initiatives and mass-transit options to reduce hydrocarbon emissions and thus reduce the risk for nonoccupational exposure for the residents of Mexico City.
authors.affiliation: Division of Laboratory Sciences, National Center for Environmental Health/Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3724, USA. SGL4@CDC.GOV
authors.forename: Sharon
authors.initials: S
authors.lastname: Lemire
authors.forename: David
authors.initials: D
authors.lastname: Ashley
authors.forename: Patricia
authors.initials: P
authors.lastname: Olaya
authors.forename: Isabelle
authors.initials: I
authors.lastname: Romieu
authors.forename: Susan
authors.initials: S
authors.lastname: Welch
authors.forename: Fernando
authors.initials: F
authors.lastname: Meneses-González
authors.forename: Mauricio
authors.initials: M
authors.lastname: Hernández-Avila
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000097:blood*; D001554:Benzene / Q000032:analysis; D001555:Benzene Derivatives / Q000097:blood; D005260:Female; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D008738:Methyl Ethers / Q000097:blood; D008800:Mexico; D008875:Middle Aged; D014050:Toluene / Q000097:blood; D014186:Transportation; D014505:Urban Population; D014992:Xylenes / Q000097:blood
chemical_list: D000393:Air Pollutants; D001555:Benzene Derivatives; D008738:Methyl Ethers; D014992:Xylenes; C043243:methyl tert-butyl ether; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene