title: Traffic-related exposures, airway function, inflammation, and respiratory symptoms in children.
abstract: BACKGROUND
  Traffic-related emissions have been associated with respiratory symptoms in some studies. However, there is limited information on how traffic-related emissions relate to lung function and airway inflammation.
  
  
  OBJECTIVE
  To determine the differential association of traffic-related exposures with exhaled nitric oxide (NO) and lung volumes and symptoms in children with and without asthma.
  
  
  METHODS
  We performed a longitudinal study of 200 children from ages 6 to 12 years of whom half had physician-diagnosed asthma. Two-week NO(2) and 48-hour average levels of elemental carbon and particulate matter of less than 2.5 microm (PM(2.5)) were measured at participating schools. Road and traffic densities were determined at schools and at each participant's house.
  
  
  RESULTS
  In children with asthma, an interquartile increase in road density within the 50-, 100-, and 200-m home buffer areas was associated with increased exhaled NO (50 m: 28%; P = 0.03; 95% confidence interval [CI], 3-60; 100 m: 27%; P = 0.005; 95% CI, 8-49; 200 m: 17%, P = 0.09, 95% CI, -2 to 40), and reduced FEV(1) (50 m: -0.091 L; P = 0.038; 95% CI, -0.174 to -0.007; 100 m: -0.072 L, P = -0.028, 95% CI, -0.134 to -0.009; 200 m: -0.106 L, P = 0.002, 95% CI, -0.171 to -0.041]). Exposure to NO(2) at schools was marginally associated with reduced FEV(1) (-0.020; P = 0.060; 95% CI, -0.042 to 0.001). We did not observe significant associations with PM(2.5) or elemental carbon on exhaled NO. We did not observe significant reductions in lung volumes or changes in exhaled NO among healthy children.
  
  
  CONCLUSIONS
  Vehicular traffic exposures are associated with increased levels of exhaled NO and reduced lung volumes in children with asthma.
authors.affiliation: Emory University, Atlanta, Georgia, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: Holguin
authors.forename: Silvia
authors.initials: S
authors.lastname: Flores
authors.forename: Zev
authors.initials: Z
authors.lastname: Ross
authors.forename: Marlene
authors.initials: M
authors.lastname: Cortez
authors.forename: Mario
authors.initials: M
authors.lastname: Molina
authors.forename: Luisa
authors.initials: L
authors.lastname: Molina
authors.forename: Carlos
authors.initials: C
authors.lastname: Rincon
authors.forename: Michael
authors.initials: M
authors.lastname: Jerrett
authors.forename: Kiros
authors.initials: K
authors.lastname: Berhane
authors.forename: Alfredo
authors.initials: A
authors.lastname: Granados
authors.forename: Isabelle
authors.initials: I
authors.lastname: Romieu
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D001249:Asthma / Q000378:metabolism / Q000503:physiopathology*; D001336:Automobiles; D001944:Breath Tests; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D012574:Schools; D013147:Spirometry; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D009569:Nitric Oxide