title: Aerosol penetration and leakage characteristics of masks used in the health care industry.
abstract: BACKGROUND
  Historically, surgical masks have been worn to protect patients from being infected by large, pathogen-containing aerosol droplets emitted by health care personnel. Today, emphasis has shifted from solely protecting the patient to protecting the health care worker as well. As a result of new procedures used in operating rooms and clinical areas, aerosolized hazardous agents in the submicrometer size range are being produced, posing a potential threat to health care workers.
  
  
  METHODS
  Eight surgical masks were tested for aerosol particle penetration through their filter media and through induced face-seal leaks.
  
  
  RESULTS
  The percentage of filter penetration ranged from 20% to nearly 100% for submicrometer-sized particles. In comparison, a dust-mist-fume respirator used in industrial settings had significantly less penetration through its filter medium. When the surgical masks had artificially induced face-seal leaks, the concentration of submicrometer-sized particles inside the mask increased slightly; in contrast, the more protective dust-mist-fume respirator showed a fourfold increase in aerosol penetration into the mask with an artificial leak 4 mm in diameter.
  
  
  CONCLUSIONS
  We conclude that the protection provided by surgical masks may be insufficient in environments containing potentially hazardous submicrometer-sized aerosols.
authors.affiliation: Department of Environmental Health, University of Cincinnati, OH.
authors.forename: A
authors.initials: A
authors.lastname: Weber
authors.forename: K
authors.initials: K
authors.lastname: Willeke
authors.forename: R
authors.initials: R
authors.lastname: Marchioni
authors.forename: T
authors.initials: T
authors.lastname: Myojo
authors.forename: R
authors.initials: R
authors.lastname: McKay
authors.forename: J
authors.initials: J
authors.lastname: Donnelly
authors.forename: F
authors.initials: F
authors.lastname: Liebhaber
mesh_terms: D000336:Aerosols; D005069:Evaluation Studies as Topic; D005374:Filtration; D006801:Humans; D017053:Infection Control; D017758:Infectious Disease Transmission, Patient-to-Professional / Q000517:prevention & control*; D008397:Masks / Q000592:standards*; D010316:Particle Size; D010564:Personnel, Hospital
chemical_list: D000336:Aerosols