AEROSOL PENETRATION AND LEAKAGE CHARACTERISTICS OF MASKS USED IN THE HEALTH-CARE INDUSTRY

Background: Historically, surgical masks have been worn to protect pat ients from being infected by large, pathogen-containing aerosol drople ts emitted by health care personnel. Today, emphasis has shifted from solely protecting die patient to protecting the health carr worker as well. As a result of new procedures used in operating rooms and clinic al 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 penetr ation through their filter media and through induced face-seal leaks. Results: The percentage of filter penetration ranged from 20% to nearl y 100% for submicrometer-sized particles. In comparison, a dust-mist-f ume respirator used in industrial settings had significantly less pene tration through its filter medium. When the surgical masks had artific ially induced face-seal leaks, the concentration of submicrometer-size d particles inside the mask increased slightly, in contrast, the more protective dust-mist-fume respirator showed a fourfold increase in aer osol penetration into the mask with an artificial leak 4 mm in diamete r. Conclusion: We conclude that the protection provided by surgical ma sks may be insufficient in environments containing potentially hazardo us submicrometer-sized aerosols.