title: Symptoms in response to controlled diesel exhaust more closely reflect exposure perception than true exposure.
abstract: BACKGROUND
  Diesel exhaust (DE) exposures are very common, yet exposure-related symptoms haven't been rigorously examined.
  
  
  OBJECTIVE
  Describe symptomatic responses to freshly generated and diluted DE and filtered air (FA) in a controlled human exposure setting; assess whether such responses are altered by perception of exposure.
  
  
  METHODS
  43 subjects participated within three double-blind crossover experiments to order-randomized DE exposure levels (FA and DE calibrated at 100 and/or 200 micrograms/m(3) particulate matter of diameter less than 2.5 microns), and completed questionnaires regarding symptoms and dose perception.
  
  
  RESULTS
  For a given symptom cluster, the majority of those exposed to moderate concentrations of diesel exhaust do not report such symptoms. The most commonly reported symptom cluster was of the nose (29%). Blinding to exposure is generally effective. Perceived exposure, rather than true exposure, is the dominant modifier of symptom reporting.
  
  
  CONCLUSIONS
  Controlled human exposure to moderate-dose diesel exhaust is associated with a range of mild symptoms, though the majority of individuals will not experience any given symptom. Blinding to DE exposure is generally effective. Perceived DE exposure, rather than true DE exposure, is the dominant modifier of symptom reporting.
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America.
authors.forename: Chris
authors.initials: C
authors.lastname: Carlsten
authors.affiliation: Children's Core For Biomedical Statistics, Seattle Children's Research Institute, Seattle, Washington, United States of America.
authors.forename: Assaf P
authors.initials: AP
authors.lastname: Oron
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America.
authors.forename: Heidi
authors.initials: H
authors.lastname: Curtiss
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America.
authors.forename: Sara
authors.initials: S
authors.lastname: Jarvis
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America ; Department of Medicine, University of Washington, Seattle, Washington, United States of America.
authors.forename: William
authors.initials: W
authors.lastname: Daniell
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America ; Department of Medicine, University of Washington, Seattle, Washington, United States of America.
authors.forename: Joel D
authors.initials: JD
authors.lastname: Kaufman
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000633:toxicity; D018592:Cross-Over Studies; D004311:Double-Blind Method; D018876:Environmental Illness / Q000209:etiology / Q000523:psychology; D005260:Female; D005742:Gasoline; D006801:Humans; D019570:Inhalation Exposure / Q000706:statistics & numerical data; D008297:Male; D009784:Occupational Diseases / Q000209:etiology / Q000523:psychology; D052638:Particulate Matter / Q000633:toxicity; D010465:Perception; D001335:Vehicle Emissions / Q000633:toxicity*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D005742:Gasoline; D052638:Particulate Matter; D001335:Vehicle Emissions