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Environ Health Perspect. 2002 Jan; 110(1): 95–101.
PMCID: PMC1240698
PMID: 11781170
Research Article

The characterization of upper-room ultraviolet germicidal irradiation in inactivating airborne microorganisms.

Gwangpyo Ko, Melvin W First, and Harriet A Burge
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Abstract

In this study, we explored the efficacy of upper-room ultraviolet germicidal irradiation (UVGI) in reducing the concentration of Serratia marcescens and Mycobacterium bovis bacille Calmette-Guérin (BCG) aerosols in enclosed places. We constructed a facility (4.5 m x 3 m x 2.9 m) in which both ceiling- and wall-mounted UV fixtures (UV output: 10W and 5W respectively) were installed. The use of ceiling- and wall-mounted UV fixtures (total UV output: 15W) without mixing fan reduced the concentration of S. marcescens aerosols by 46% (range: 22-80%) at 2 air changes per hour (ACH) and 53% (range: 40-68%) at 6 ACH. The use of ceiling- and wall-mounted UV fixtures with mixing fan increased the UV effectiveness in inactivating S. marcescens aerosols to 62% (range: 50-78%) at 2 ACH and to 86% (81-89%) at 6 ACH. For BCG aerosols, UV effectiveness in inactivating BCG aerosols at 6 ACH were 52% (range: 11-69%) by ceiling-mounted UV fixture only (total UV output: 10W) and 64% (51-83%) by both ceiling- and wall-mounted UV fixtures (total UV output: 15W). Our results indicated that the equivalent ventilation rate attributable to upper-room UVGI for BCG aerosols ranged from 1 ACH to 22 ACH for ceiling-mounted UV fixtures and from 6.4 ACH to 28.5 ACH for ceiling- and wall-mounted UV fixtures. Both generalized linear and generalized additive models were fitted to all our data. The regression results indicated that the number of UV fixtures, use of mixing fan, and air exchange rate significantly affected UV effectiveness (p < 0.01, 0.01, 0.01 respectively). However, the strain difference (S. marcescens vs. BCG) appeared less important in UV effectiveness (p = 0.26). Our results also indicated that UV effectiveness increased at higher temperature ((italic)p(/italic) < 0.01), lower dry-bulb temperature ((italic)p(/italic) = 0.21), and colder air from a supply grill located near the ceiling (p = 0.22).

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Selected References

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  • Barnes PF, Yang Z, Preston-Martin S, Pogoda JM, Jones BE, Otaya M, Eisenach KD, Knowles L, Harvey S, Cave MD. Patterns of tuberculosis transmission in Central Los Angeles. JAMA. 1997 Oct 8;278(14):1159–1163. [PubMed] [Google Scholar]
  • Nardell EA, Brickner PW. Tuberculosis in New York City: focal transmission of an often fatal disease. JAMA. 1996 Oct 16;276(15):1259–1260. [PubMed] [Google Scholar]
  • Pablos-Méndez A, Raviglione MC, Laszlo A, Binkin N, Rieder HL, Bustreo F, Cohn DL, Lambregts-van Weezenbeek CS, Kim SJ, Chaulet P, et al. Global surveillance for antituberculosis-drug resistance, 1994-1997. World Health Organization-International Union against Tuberculosis and Lung Disease Working Group on Anti-Tuberculosis Drug Resistance Surveillance. N Engl J Med. 1998 Jun 4;338(23):1641–1649. [PubMed] [Google Scholar]
  • Nardell EA. Interrupting transmission from patients with unsuspected tuberculosis: a unique role for upper-room ultraviolet air disinfection. Am J Infect Control. 1995 Apr;23(2):156–164. [PubMed] [Google Scholar]
  • Ko G, Burge HA, Nardell EA, Thompson KM. Estimation of tuberculosis risk and incidence under upper room ultraviolet germicidal irradiation in a waiting room in a hypothetical scenario. Risk Anal. 2001 Aug;21(4):657–673. [PubMed] [Google Scholar]
  • Riley RL, Knight M, Middlebrook G. Ultraviolet susceptibility of BCG and virulent tubercle bacilli. Am Rev Respir Dis. 1976 Apr;113(4):413–418. [PubMed] [Google Scholar]
  • Riley RL, Permutt S, Kaufman JE. Convection, air mixing, and ultraviolet air disinfection in rooms. Arch Environ Health. 1971 Feb;22(2):200–207. [PubMed] [Google Scholar]
  • Riley RL, Permutt S. Room air disinfection by ultraviolet irradiation of upper air. Air mixing and germicidal effectiveness. Arch Environ Health. 1971 Feb;22(2):208–219. [PubMed] [Google Scholar]
  • Riley RL, Kaufman JE. Air disinfection in corridors by upper air irradiation with ultraviolet. Arch Environ Health. 1971 May;22(5):551–553. [PubMed] [Google Scholar]
  • Theunissen HJ, Lemmens-den Toom NA, Burggraaf A, Stolz E, Michel MF. Influence of temperature and relative humidity on the survival of Chlamydia pneumoniae in aerosols. Appl Environ Microbiol. 1993 Aug;59(8):2589–2593. [PMC free article] [PubMed] [Google Scholar]
  • ANDERSEN AA. New sampler for the collection, sizing, and enumeration of viable airborne particles. J Bacteriol. 1958 Nov;76(5):471–484. [PMC free article] [PubMed] [Google Scholar]
  • Kethley TW, Branch K. Ultraviolet lamps for room air disinfection. Effect of sampling location and particle size of bacterial aerosol. Arch Environ Health. 1972 Sep;25(3):205–214. [PubMed] [Google Scholar]
  • Ko G, First MW, Burge HA. Influence of relative humidity on particle size and UV sensitivity of Serratia marcescens and Mycobacterium bovis BCG aerosols. Tuber Lung Dis. 2000;80(4-5):217–228. [PubMed] [Google Scholar]
  • Russell RJ, Gerike U, Danson MJ, Hough DW, Taylor GL. Structural adaptations of the cold-active citrate synthase from an Antarctic bacterium. Structure. 1998 Mar 15;6(3):351–361. [PubMed] [Google Scholar]
  • Walter MV, Marthi B, Fieland VP, Ganio LM. Effect of aerosolization on subsequent bacterial survival. Appl Environ Microbiol. 1990 Nov;56(11):3468–3472. [PMC free article] [PubMed] [Google Scholar]
  • Wathes CM, Howard K, Webster AJ. The survival of Escherichia coli in an aerosol at air temperatures of 15 and 30 degrees C and a range of humidities. J Hyg (Lond) 1986 Dec;97(3):489–496. [PMC free article] [PubMed] [Google Scholar]
  • Marthi B, Fieland VP, Walter M, Seidler RJ. Survival of bacteria during aerosolization. Appl Environ Microbiol. 1990 Nov;56(11):3463–3467. [PMC free article] [PubMed] [Google Scholar]
  • Winckler K, Fidhiany L. Combined effects of constant sublethal UVA irradiation and elevated temperature on the survival and general metabolism of the convict-cichlid fish, Cichlasoma nigrofasciatum. Photochem Photobiol. 1996 Apr;63(4):487–491. [PubMed] [Google Scholar]
  • Thoma F. Light and dark in chromatin repair: repair of UV-induced DNA lesions by photolyase and nucleotide excision repair. EMBO J. 1999 Dec 1;18(23):6585–6598. [PMC free article] [PubMed] [Google Scholar]
  • Becker MM, Wang Z. Origin of ultraviolet damage in DNA. J Mol Biol. 1989 Dec 5;210(3):429–438. [PubMed] [Google Scholar]
  • Riley RL, Kaufman JE. Effect of relative humidity on the inactivation of airborne Serratia marcescens by ultraviolet radiation. Appl Microbiol. 1972 Jun;23(6):1113–1120. [PMC free article] [PubMed] [Google Scholar]
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