title: Diesel exhaust but not ozone increases fraction of exhaled nitric oxide in a randomized controlled experimental exposure study of healthy human subjects.
abstract: BACKGROUND
  Fraction of exhaled nitric oxide (FENO) is a promising non-invasive index of airway inflammation that may be used to assess respiratory effects of air pollution. We evaluated FENO as a measure of airway inflammation after controlled exposure to diesel exhaust or ozone.
  
  
  METHODS
  Healthy volunteers were exposed to either diesel exhaust (particle concentration 300 μg/m3) and filtered air for one hour, or ozone (300 ppb) and filtered air for 75 minutes. FENO was measured in duplicate at expiratory flow rates of 10, 50, 100 and 270 mL/s before, 6 and 24 hours after each exposure.
  
  
  RESULTS
  Exposure to diesel exhaust increased FENO at 6 hours compared with air at expiratory flow rates of 10 mL/s (p = 0.01) and at 50 mL/s (p = 0.011), but FENO did not differ significantly at higher flow rates. Increases in FENO following diesel exhaust were attenuated at 24 hours. Ozone did not affect FENO at any flow rate or time point.
  
  
  CONCLUSIONS
  Exposure to diesel exhaust, but not ozone, increased FENO concentrations in healthy subjects. Differences in the induction of airway inflammation may explain divergent responses to diesel exhaust and ozone, with implications for the use of FENO as an index of exposure to air pollution.
authors.affiliation: Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Barath
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Mills
authors.forename: Ellinor
authors.initials: E
authors.lastname: Adelroth
authors.forename: Anna-Carin
authors.initials: AC
authors.lastname: Olin
authors.forename: Anders
authors.initials: A
authors.lastname: Blomberg
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D010126:Ozone / Q000633:toxicity*; D013147:Spirometry; D001335:Vehicle Emissions / Q000633:toxicity*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D009569:Nitric Oxide; D010126:Ozone