title: Decontamination of indoor air to reduce the risk of airborne infections: Studies on survival and inactivation of airborne pathogens using an aerobiology chamber.
abstract: Although indoor air can spread many pathogens, information on the airborne survival and inactivation of such pathogens remains sparse.
  
  
  
  Staphylococcus aureus and Klebsiella pneumoniae were nebulized separately into an aerobiology chamber (24.0 m3). The chamber's relative humidity and air temperature were at 50% ± 5% and 20°C ± 2°C, respectively. The air was sampled with a slit-to-agar sampler. Between tests, filtered air purged the chamber of any residual airborne microbes.
  
  
  
  The challenge in the air varied between 4.2 log10colony forming units (CFU)/m3and 5.0 log10CFU/m3, sufficient to show a ≥3 log10(≥99.9%) reduction in microbial viability in air over a given contact time by the technologies tested. The rates of biologic decay of S aureus and K pneumoniae were 0.0064 ± 0.00015 and 0.0244 ± 0.009 log10CFU/m3/min, respectively. Three commercial devices, with ultraviolet light and HEPA (high-efficiency particulate air) filtration, met the product efficacy criterion in 45-210 minutes; these rates were statistically significant compared with the corresponding rates of biologic decay of the bacteria. One device was also tested with repeated challenges with aerosolized S aureus to simulate ongoing fluctuations in indoor air quality; it could reduce each such recontamination to an undetectable level in approximately 40 minutes.
  
  
  
  The setup described is suitable for work with all major classes of pathogens and also complies with the U.S. Environmental Protection Agency's guidelines (2012) for testing air decontamination technologies.
authors.affiliation: Department of Biochemistry, Microbiology & Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada. Electronic address: ssattar@uottawa.ca.
authors.forename: Syed A
authors.initials: SA
authors.lastname: Sattar
authors.affiliation: Department of Biochemistry, Microbiology & Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Kibbee
authors.affiliation: Department of Biochemistry, Microbiology & Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Bahram
authors.initials: B
authors.lastname: Zargar
authors.affiliation: Department of Biochemistry, Microbiology & Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Wright
authors.affiliation: Reckitt Benckiser, Research & Development, Montvale, NJ.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Rubino
authors.affiliation: Reckitt Benckiser, Research & Development, Montvale, NJ.
authors.forename: M Khalid
authors.initials: MK
authors.lastname: Ijaz
mesh_terms: D000391:Air Microbiology; D016902:Air Pollution, Indoor / Q000032:analysis* / Q000517:prevention & control; D001419:Bacteria / Q000302:isolation & purification*; D003666:Decontamination / Q000295:instrumentation / Q000379:methods; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D005374:Filtration / Q000295:instrumentation / Q000379:methods; D006801:Humans; D013696:Temperature; D014466:Ultraviolet Rays
keywords: Aerobiology; air decontamination; airborne bacteria; airborne pathogens; indoor air quality