title: Correlation between co-exposures to noise and air pollution from traffic sources.
abstract: BACKGROUND
  Both air and noise pollution associated with motor vehicle traffic have been associated with cardiovascular disease. Similarities in pollution source and health outcome mean that there is potential for noise to confound studies of air pollution and cardiovascular disease, and vice versa, or for more complex interactions to occur.
  
  
  METHODS
  The correlations between 2-week average roadside concentrations of nitrogen dioxide (NO(2)) and nitrogen oxides (NO(X)) and short term average noise levels (L(eq,5min)) for 103 urban sites with varying traffic, environment and infrastructure characteristics were examined.
  
  
  RESULTS
  The Pearson correlation coefficient for L(eq,5min) and NO(2) was 0.53, and for L(eq,5min) and NO(X) , 0.64. Factors influencing the degree of correlation were number of lanes on the closest road, number of cars or trucks during noise sampling and presence of a major intersection.
  
  
  CONCLUSIONS
  We recommend measurement of both pollutants in future studies of traffic-related pollution and cardiovascular disease to allow for more sophisticated analysis of this relationship.
authors.affiliation: University of British Columbia, Vancouver, Canada. hugh.davies@ubc.ca
authors.forename: H W
authors.initials: HW
authors.lastname: Davies
authors.forename: J J
authors.initials: JJ
authors.lastname: Vlaanderen
authors.forename: S B
authors.initials: SB
authors.lastname: Henderson
authors.forename: M
authors.initials: M
authors.lastname: Brauer
mesh_terms: D000397:Air Pollution / Q000032:analysis*; D001336:Automobiles; D001955:British Columbia; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D006801:Humans; D018986:Motor Vehicles; D009585:Nitrogen Dioxide / Q000032:analysis; D009589:Nitrogen Oxides / Q000032:analysis*; D009622:Noise; D009624:Noise, Transportation / Q000706:statistics & numerical data*; D014504:Urban Health
chemical_list: D009589:Nitrogen Oxides; D009585:Nitrogen Dioxide