title: Positive effects of a fresh air filtration system on hay fever symptoms.
abstract: BACKGROUND
  Avoidance of allergen exposure is the basic preventive measure in reducing symptoms of immediate-type allergies. As room air cleaners were found to have no benefic effect on general health, their use has not been recommended. The purpose of this study was to evaluate the effect of a fresh air filtration system installed in the bedrooms of non-air-conditioned homes on hay fever symptoms.
  
  
  METHODS
  In a placebo-controlled, double-blind, two-period, crossover study, we investigated the effectiveness of a fresh air filtration system installed in the bedrooms of volunteers suffering from hay fever.
  
  
  RESULTS
  Volunteers only suffering from pollinosis reported an improvement of their allergy symptoms. We observed a significant decrease in nighttime hay fever symptoms and an increase in morning peak expiratory flow rates (PEFR). No effects were recognized in volunteers who additionally had perennial allergy.
  
  
  CONCLUSIONS
  Based upon these results, the installation of fresh air filtration systems in bedrooms should be recommended for patients suffering from hay fever.
authors.affiliation: Department of Dermatology, UKM, Münster, Germany. r.brehler@uni-muenster.de
authors.forename: Randolf
authors.initials: R
authors.lastname: Brehler
authors.forename: Birgitta
authors.initials: B
authors.lastname: Kütting
authors.forename: Klaus
authors.initials: K
authors.lastname: Biel
authors.forename: Thomas
authors.initials: T
authors.lastname: Luger
mesh_terms: D000328:Adult; D000389:Air Conditioning; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005374:Filtration; D006801:Humans; D008297:Male; D006255:Rhinitis, Allergic, Seasonal / Q000517:prevention & control*