title: Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity.
abstract: Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs). Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%-92% and temperature increased to 29-30 °C. S. aureus survived the best on filter materials with 40%-200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48-72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.
authors.affiliation: Department of Personal Protective Equipment, Central Institute for Labour Protection-National Research Institute, Łódź 90-133, Poland. kamaj@ciop.lodz.pl.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Majchrzycka
authors.affiliation: Department of Personal Protective Equipment, Central Institute for Labour Protection-National Research Institute, Łódź 90-133, Poland. maokr@ciop.lodz.pl.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Okrasa
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Łódź 90-924, Poland. justyna-skora@wp.pl.
authors.forename: Justyna
authors.initials: J
authors.lastname: Skóra
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Łódź 90-924, Poland. beata.gutarowska@p.lodz.pl.
authors.forename: Beata
authors.initials: B
authors.lastname: Gutarowska
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D049109:Cell Proliferation; D006813:Humidity; D016273:Occupational Exposure; D011482:Protective Devices / Q000382:microbiology*; D012134:Respiratory Protective Devices / Q000382:microbiology*; D013696:Temperature
keywords: FRPDs; filter material; filtering respiratory protective devices; humidity conditions; microorganisms