Determining the performance of a commercial air purification system for reducing airborne contamination using model micro-organisms: a new test methodology.
The performance of a duct-mounted air disinfection system, designed to reduce airborne pathogens in the hospital environment, was determined using a new testing methodology. The methodology places the equipment in a test duct, a microbial aerosol is generated and then sampled simultaneously before and after the test system. This allows a percentage efficiency value to be calculated. The air disinfection system is a novel chemical-coated filter and ultraviolet (UV) radiation air purification system, operating at a flow rate of 500 m(3)/h, against aerosols of MS2 phage and Mycobacterium vaccae (surrogates of viral and mycobactericidal pathogens). A three UV lamp system was effective against airborne phages, removing an average of 97.34% of the aerosolized challenge. With the UV component switched off, the average efficiency dropped to 61.46%. This demonstrates that the chemical-coated filter component plays a more significant role than the UV radiation in destroying phages. When six UV lamps were used, the system was able to remove mycobacteria with an efficiency exceeding 99.99%. This test methodology can be used to assess manufacturers' claims of efficacy of equipment against airborne micro-organisms in the hospital environment.
Griffiths
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Airborne Matters, 47 Manor Road, Toddington, Dunstable LU5 6AJ, UK. anndai@griffiths47.fsnet.co.uk
Bennett
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A
Speight
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Parks
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D000391:Air Microbiology; D016902:Air Pollution, Indoor / Q000517:prevention & control*; D003428:Cross Infection / Q000517:prevention & control*; D004203:Disinfection / Q000379:methods*; D005374:Filtration; D017909:Levivirus / Q000254:growth & development; D009161:Mycobacterium / Q000254:growth & development