Air Filtration of Microbial Particles

Decker, Herbert M.; Buchanan, Lee M.; Hall, Lenwood W.; Goddard, K.R.

doi:10.2105/ajph.53.12.1982

Cited by 34 publications

(17 citation statements)

References 0 publications

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“…Chemical Corps Type 6 filter paper. This material is an ultrahigh-efficiency filter paper composed of cellulose, rope, and asbestos fibers (Decker et al, 1962). The filter discs (2.5 cm in diameter) were sealed in in-line filter holders with an effective area of 2.0 cm2 (Wolf et al, 1959).…”

Section: Downloaded Frommentioning

confidence: 99%

Sampling Submicron T1 Bacteriophage Aerosols

Harstad¹

1965

Applied Microbiology

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HARSTAD, J. BRUCE (Fort Detrick, Frederick, Md.). Sampling submicron Ti bacteriophage aerosols. Appl. Microbiol. 13:899-908. 1965.-Liquid impingers, filter papers, and fritted bubblers were partial viable collectors of radioactive submicron Ti bacteriophage aerosols at 30, 55, and 85% relative humidity. Sampler differences for viable collection were due to incomplete physical collection (slippage) and killing of phage by the samplers. Dynamic aerosols of a mass median diameter of 0.2 IA were produced with a Dautrebande generator from concentrated aqueous purified phage suspensions containing extracellular soluble radioactive phosphate as a physical tracer. There was considerable destruction of phage by the Dautrebande generator; phage titers of the Dautrebande suspension decreased exponentially, but there was a progressive (linear) increase in tracer titers. Liquid impingers recovered the most viable phage but allowed considerable (30 to 48%) slippage, which varies inversely with the aerosol relative humidity. Filter papers were virtually complete physical collectors of submicron particles but were the most destructive. Fritted bubbler slippage was more than 80%. With all samplers, phage kill was highest at 85% relative humidity and lowest at 55% relative humidity. An electrostatic precipitator was used to collect aerosol samples for particle sizing with an electron microscope. The particle size was slightly larger at 85% relative humidity than at 30 or 55% relative humidity. 899 on July 3, 2020 by guest http://aem.asm.org/ Downloaded from nonu8 HARSTAD on July 3, 2020 by guest http://aem.asm.org/ Downloaded from

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Section: Downloaded Frommentioning

confidence: 99%

Sampling Submicron T1 Bacteriophage Aerosols

Harstad¹

1965

Applied Microbiology

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“…Filters were divided into four classes according to their efficiency: (i) low-efficiency, (ii) medium-efficiency, (iii) high-efficiency, and (iv) ultrahigh-efficiency filters [9]. A HEPA filter has a 99.999% removal rate for a particle size of 0.3 µm.…”

Section: Discussionmentioning

confidence: 99%

Survival of Microorganisms on Antimicrobial Filters and the Removal Efficiency of Bioaerosols in an Environmental Chamber

Kim

Kim²,

Lee³

et al. 2012

J. Microbiol. Biotechnol.

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Exposure to bioaerosols causes various adverse health effects including infectious and respiratory diseases, and hypersensitivity. Controlling exposure to bioaerosols is important for disease control and prevention. In this study, we evaluated the efficacies of various functional filters coated with antimicrobial chemicals in deactivating representative microorganisms on filters or as bioaerosols. Tested functional filters were coated with different chemicals that included (i) Ginkgo and sumac, (ii) Ag-apatite and guanidine phosphate, (iii) SiO 2 , ZnO, and Al 2 O 3 , and (iv) zeolite. To evaluate the filters, we used a model ventilation system (1) to evaluate the removal efficiency of bacteria (Escherichia coli and Legionella pneumophila), bacterial spores (Bacillus subtilis spore), and viruses (MS2 bacteriophage) on various functional filters, and (2) to characterize the removal efficiency of these bioaerosols. All experiments were performed at a constant temperature of 25ºC and humidity of 50%. Most bacteria (excluding B. subtilis) rapidly decreased on the functional filter. Therefore, we confirmed that functional filters have antimicrobial effects. Additionally, we evaluated the removal efficiency of various bioaerosols by these filters. We used a six-jet collision nebulizer to generate microbial aerosols and introduced it into the environmental chamber. We then measured the removal efficiency of functional filters with and without a medium-efficiency filter. Most bioaerosol concentrations did not significantly decrease by the functional filter only but decreased by a combination of functional and medium-efficiency filter. In conclusion, functional filters could facilitate biological removal of various bioaerosols, but physical removal of these by functional was minimal. Proper use of chemical-coated filter materials could reduce exposure to these agents.

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“…The air passes through a roughing filter and then a HEPA (high efficiency particulate air) filter of 99.97 per cent dioctylphthalate (DOP) efficiency for removal of particles larger than 0.3 microns in diameter. 15 The filtered air passes through the duct into a plenum chamber covering the entire roof of the clean room (Figures 1 and 2). From the plenum the air moves through the ceiling via small critical orifices numbering 1,154 per square foot of ceiling.…”

Section: Methodsmentioning

confidence: 99%