Effect of Ultraviolet Germicidal Lamps on Airborne Microorganisms in an Outpatient Waiting Room

Macher, Janet M.; Alevantis, L. E.; Chang, YongKeun; Liu, K.-S.

doi:10.1080/1047322x.1992.10390201

Cited by 64 publications

(42 citation statements)

References 23 publications

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“…The lower limit (30 colonies) is to obtain suf cient statistical power for comparison purposes. The limit (300 colonies) is the maximum range in which one could easily count and differentiate colonies (Jensen et al 1994;Chang et al 1994). There was only 1 sampling port, and samples were taken in sequence rst without and then with UVGI irradiation.…”

Section: Aerosol Test System (As Shown Inmentioning

confidence: 99%

“…Moreover, a twelve-fold bacterial colony reduction was reported in 475 an operating room with a high level of UVGI at 290 ¹W/cm 2 (Lidwell 1994). In a well-ventilated hospital waiting room equipped with wall-mounted lamps, it was demonstrated that there was a 14-19% reduction in culturable bacterial concentrations (Macher et al 1992(Macher et al , 1994. Therefore UVGI should be a very promising technique for indoor microorganism control.…”

Section: Introductionmentioning

confidence: 99%

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Control Effectiveness of Ultraviolet Germicidal Irradiation on Bioaerosols

Lin

2002

Aerosol Science and Technology

101

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Because of increasing incidence of microorganism infections, there are concerns in engineering control of indoor microorganism for reducing airborne infectious diseases. Ultraviolet germicidal irradiation (UVGI) was considered to be promising to inactivate microorganisms. In this investigation, the in uences of UV dosage, microorganism species, and relative humidity on UVGI effectiveness were evaluated in a laboratory test chamber. A Collison nebulizer generated aerosols containing Escherichia coli, Bacillus subtilis spores, cells of Candida famata var. areri, and spores of Penicillium citrinum. The UVGI control effectiveness was determined as the ratio, NS=N 0 , where NS and N 0 were the colony concentrations collected by Andersen one-stage samplers at UVGI dosages of D and zero, respectively. In regard to 99% microorganism inactivation, the UVGI dosage ranges were 1017 to 2356 ¹W s/cm 2 , 15949 to 19345 ¹W s/cm 2 , 12917 to 17497 ¹W s/cm 2 , and 47984 to 89419 ¹W s/cm 2 for E. coli, B. subtilis, yeast, and P. citrinum, respectively. Signi cantly, the microorganism susceptibilities of E. coli were the highest and P. citrinum were the lowest. In regard to relative humidity effects, it was observed that the microorganism susceptibilities at 80% relative humidity were lower than those found at 50% relative humidity for all 4 types of the evaluated microorganisms.

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Section: Aerosol Test System (As Shown Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Control Effectiveness of Ultraviolet Germicidal Irradiation on Bioaerosols

Lin

2002

Aerosol Science and Technology

101

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“…UVGI has advantages and disadvantages relative to other engineering controls (Macher 1993;CDC 1994;NIOSH 1997) and has returned to the arsenal of TB control measures because of its low cost, ease of application, and potential ef cacy, despite past failure in some settings to reduce the concentration of airborne microorganisms substantially (Goldner et al 1980;Macher et al 1992Macher et al , 1994 or to prevent airborne disease transmission (Nardell 1995).…”

Section: Introductionmentioning

confidence: 99%

“…Lidwell (1994) reported a twelve-fold reduction in viable, ambient airborne bacteria in an operating room with high levels of UVGI (290 l W cm ¡ 2 ). Macher et al (1992Macher et al ( , 1994) saw a 14-19% reduction in the concentration of viable, ambient bacteria in a well-ventilated hospital waiting room equipped with wall-mounted lamps.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Methodology for Quantifying the Effect of Room Air Ultraviolet Germicidal Irradiation on Airborne Bacteria

Miller¹,

Macher²

2000

Aerosol Science and Technology

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ABSTRACT. As a result of the recent resurgence in tuberculosis (TB) and the increasing incidence of multidrug-resistant TB, there has been renewed interest in engineering controls to reduce the spread of TB and other airborne infectious diseases in high-risk settings. Techniques such as the use of lamps that produce ultraviolet germicidal radiation may reduce exposure to infectious agents by inactivating or killing microorganisms while they are airborne. We designed and evaluated a test method to quantitatively estimate the ef cacy of germicidal lamps, in conjunction with dilution ventilation, for reducing the concentration of viable airborne bacteria. Bacterial particles were generated in a 36 m 3 room and collected with midget impingers at 5 -7 locations. The effectiveness of the control technique was determined by comparing concentrations of culturable airborne bacteria with and without the control in operation. Results for a single, 15 W germicidal lamp showed reductions of 50% for Bacillus subtilis (B. subtilis) and Micrococcus luteus (M. luteus); tests with Escherichia coli (E. coli) showed nearly 100% reduction (E. coli were isolated only from the sampler nearest the aerosol source when the lamp was operating). The addition of louvers to a lamp greatly reduced its ef cacy. Decay experiments showed that roughly 4 -6 equivalent air changes per hour were achieved for B. subtilis with one or two lamps operating. These preliminary experiments demonstrated that this methodology was well suited for these evaluations and identi ed factors that could be modi ed to re ne the study design for future work.

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“…Modern living standards and building systems have increased the numbers of settings that have relatively high concentrations of bioaerosols (high-exposure environments), which have been implicated to increase cases of respiratory and pulmonary diseases. [1][2][3] These high-exposure environments include correctional facilities, 4 healthcare facilities, 5,6 shelters for the homeless, wastewater treatment plants, 7 and public transit systems. 8 More recently, buildings housing hospital therapy pools, "hot tubs," and other warm-water leisure and therapy pools have been implicated to support and aerosolize microorganisms that include opportunistic pathogens from the genera Legionella and Mycobacterium, 9 -11 causing diseases such as "lifeguard lung."…”

Section: Introductionmentioning

confidence: 99%

Effects of Ceiling-Mounted HEPA-UV Air Filters on Airborne Bacteria Concentrations in an Indoor Therapy Pool Building

Kujundzic

Zander

Hernandez

et al. 2005

Journal of the Air & Waste Management Association

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The purpose of this study was to assess the effectiveness of a new generation of high-volume, ceiling-mounted highefficiency particulate air (HEPA)-ultraviolet (UV) air filters (HUVAFs) for their ability to remove or inactivate bacterial aerosol. In an environmentally controlled full-scale laboratory chamber (87 m 3 ), and an indoor therapy pool building, the mitigation ability of air filters was assessed by comparing concentrations of total bacteria, culturable bacteria, and airborne endotoxin with and without the air filters operating under otherwise similar conditions. Controlled chamber tests with pure cultures of aerosolized Mycobacterium parafortuitum cells showed that the HUVAF unit tested provided an equivalent air-exchange rate of 11 hr Ϫ1 . Using this equivalent air-exchange rate as a design basis, three HUVAFs were installed in an indoor therapy pool building for bioaerosol mitigation, and their effectiveness was studied over a 2-year period. The HUVAFs reduced concentrations of culturable bacteria by 69 and 80% during monitoring periods executed in respective years. The HUVAFs reduced concentrations of total bacteria by 12 and 76% during the same monitoring period, respectively. Airborne endotoxin concentrations were not affected by the HUVAF operation.

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Effect of Ultraviolet Germicidal Lamps on Airborne Microorganisms in an Outpatient Waiting Room

Cited by 64 publications

References 23 publications

Control Effectiveness of Ultraviolet Germicidal Irradiation on Bioaerosols

Control Effectiveness of Ultraviolet Germicidal Irradiation on Bioaerosols

Evaluation of a Methodology for Quantifying the Effect of Room Air Ultraviolet Germicidal Irradiation on Airborne Bacteria

Effects of Ceiling-Mounted HEPA-UV Air Filters on Airborne Bacteria Concentrations in an Indoor Therapy Pool Building

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