title: Air pollutants enhance rhinoconjunctivitis symptoms in pollen-allergic individuals.
abstract: BACKGROUND
  Little is know about the relation of airborne pollen allergens to nasal and ocular symptoms in combination with air pollutants.
  
  
  OBJECTIVE
  The hypothesis was that air pollutants exacerbate allergic symptoms of the nose and eyes during the pollen season. In addition, the use of allergen measurements instead of pollen counts should be tested.
  
  
  METHODS
  Fifteen pollen-allergic, nonsmoking subjects with weak reactivity of the airways recorded rhinoconjunctival symptoms and medication every morning and evening throughout the pollen season. Symptoms were compared with air pollutants (nitrogen oxide [NOx], particulate matter smaller than 10 microm, and ozone) and birch and grass pollen counts or, alternatively, to airborne birch and grass allergens determined using ELISA-techniques. A multiple linear regression model was used which controlled for autocorrelation of the residuals of the time series (Cochrane-Orcutt approach). This model was applied to each subject individually, followed by calculations of summary scores for the group.
  
  
  RESULTS
  Air pollution levels were moderate, often meeting air quality standards. Effect estimates (increase of score with 10-fold increase of concentration) were NOx = 1.06, P < 0.01; ozone = 1.59, P < 0.01; and pollen = 0.48, P < 0.001. Using allergen concentrations instead of pollen counts resulted in similar effect estimates. Using particulate matter smaller than 10 microm instead of NOx gave comparable but less consistent results.
  
  
  CONCLUSIONS
  Symptoms were related to moderate levels of pollutants, suggesting that rhinoconjunctival tissue is very sensitive to irritant stimuli during an ongoing allergic inflammation, and that susceptibility toward allergens might be increased in areas with increased levels of air pollutants. Allergen measurements seem equally usable as pollen counts to investigate rhinoconjunctivitis.
authors.affiliation: Institute for Hygiene and Applied Physiology, Environmental Hygiene Section, Swiss Federal Institute of Technology, Zurich. michael.riediker@alumni.ethz.ch
authors.forename: M
authors.initials: M
authors.lastname: Riediker
authors.forename: C
authors.initials: C
authors.lastname: Monn
authors.forename: T
authors.initials: T
authors.lastname: Koller
authors.forename: W A
authors.initials: WA
authors.lastname: Stahel
authors.forename: B
authors.initials: B
authors.lastname: Wüthrich
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects*; D000485:Allergens / Q000009:adverse effects / Q000032:analysis; D029662:Betula / Q000276:immunology; D003233:Conjunctivitis, Allergic / Q000175:diagnosis / Q000209:etiology*; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D009589:Nitrogen Oxides / Q000009:adverse effects; D010126:Ozone / Q000009:adverse effects; D006109:Poaceae / Q000276:immunology; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000209:etiology*
chemical_list: D000393:Air Pollutants; D000485:Allergens; D009589:Nitrogen Oxides; D010126:Ozone