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Abstract
Background:
Surgical masks are used in hospitals to reduce postoperative infection in patients. The presence of aerosols containing pathogens makes it desirable to protect the medical staff as well.
Methods:
The collection efficiencies of surgical masks were measured with two aerosol-size spectrometers. The flow rates through the masks were varied from 5 to 100 L/min to study the flow dependency. For comparison, several industrial-type respirators were also tested.
Results:
A surgical mask consisting of filter material performed better than did a surgical mask consisting only of a shell with a coarse pore structure. The latter passed 80% of submicrometer-sized aerosols with little flow dependency, whereas the penetration of submicrometer-sized aerosols through the mask made of filter material ranged from 25% at a flow rate of 5 L/min to 70% at 100 L/min.
Conclusions:
The mask that has the highest collection efficiency is not necessarily the best mask from the perspective of the filter-quality factor, which considers not only the capture efficiency but also the air resistance. Although surgical mask media may be adequate to remove bacteria exhaled or expelled by health care workers, they may not be sufficient to remove the submicrometer-sized aerosols containing pathogens to which these health care workers are potentially exposed.
References
- The surgical mask unmasked: a review.Oral Surg Oral Med Oral Pathol. 1990; 70: 34-36
- The shouting surgeon as a possible source of endiphthalmitis.Ophthal Surg. 1990; 21: 438-440
- Possible hazards from irradiation with the carbon dioxide laser.Lasers Surg Med. 1986; 6: 84-86
- Smoke from laser surgery: is there a health hazard?.Lasers Surg Med. 1987; 7: 376-382
- Infectious papillomavirus in the vapor of warts treated with carbon dioxide laser or electrocoagulation: detection and protection.J Am Acad Dermatol. 1989; 21: 41-49
- Aerosol created by some surgical power tools: particle size distribution and qualitative hemoglobin content.Appl Occup Environ Hyg. 1991; 6: 773-776
- The efficiency of surgical masks of varying design and composition.Br J Surg. 1975; 62: 936-940
- Method for evaluation effectiveness of surgical masks.J Bacteriol. 1962; 83: 663-667
- Microbial filtration by surgical masks.Surg Gynecol Obstet. 1971; 133: 812-814
- An investigation into the efficiency of disposable face masks.J Clin Pathol. 1980; 33: 1086-1091
- Face seal leakage of half masks and surgical masks.Am Ind Hyg Assoc J. 1985; 46: 308-312
- Common material for emergency respiratory protection: leakage tests with a manikin.Am Ind Hyg Assoc J. 1983; 44: 720-726
- A rapid latex filtration efficiency test method for simulating bacterial filtration efficiency.Particulate Microb Control. 1983; 3: 30-37
- Is a mask necessary in the operating theatre?.Ann R Coll Surg Engl. 1981; 63: 390-392
- Face masks: which, when, where, and why?.J Hosp Infect. 1981; 2: 1-4
- Masks: a ward investigation and review of the literature.J Hosp Infect. 1986; 7: 289-294
- Filtration efficiency of surgical face masks: the need for more meaningful standards.Am J Infect Control. 1991; 19: 16-18
- New methods for quantitative respirator fit testing with aerosols.Am Ind Hyg Assoc J. 1981; 42: 121-125
- Noninvasive, quantitative respirator fit testing through dynamic pressure measurement.Am Ind Hyg Assoc J. 1988; 49: 485-491
- Simplified pressure method for respirator fit testing.Am Ind Hyg Assoc J. 1991; 52: 305-308
- Labor. Code of federal regulation title 29, part 1910.134. Office of the Federal Register, National Archives and Records Administration, Washington DC1988: 726-734
- (2nd printing)1990–1991 threshold limit values for chemical substances and physical agents and biological exposure indices.ACGIH, Cincinnati1990
- Mineral resources. Code of federal regulation title 30, part 11. Office of the Federal Register, National Archives and Records Administration, Washington DC1983: 7-71
- Filter and leak penetration of a dust and mist filtering facepieces.Am Ind Hyg Assoc J. 1990; 51: 632-639
- Size-fractionating aerosol generator.Aerosol Sci Technol. 1990; 13: 450-458
- Focus on present procedures in quantitative respirator fit testing: problems and potential solutions.Appl Occup Environ Hyg. 1990; 5: 762-765
- Respirator fit and protection through determination of air and particle leakage.Ann Occup Hyg. 1991; 35: 13-24
- Assigned protection factors for two respirator types based upon workplace performance testing.Ann Occup Hyg. 1984; 28: 173-182
- Variability in protection afforded by half-mask respirators against styrene exposure in the field.Am Ind Hyg Assoc J. 1990; 51: 625-631
Article Info
Footnotes
*Supported by National Institute for Occupational Safety and Health grant no. R01-OH-01301. Dr. Chen supported by a stipend for graduate education, University of Cincinnati, during part of this study.
Identification
Copyright
© 1992 the Association for Practitioners in Infection Control, Inc. All rights reserved. Published by Elsevier Inc.
