Viability of B. Coli Exposed to Ultra-Violet Radiation in Air

Wells, W. F.; Fair, Gordon M.

doi:10.1126/science.82.2125.280-a

Cited by 55 publications

(28 citation statements)

References 1 publication

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“…A number of infectious microorganisms and viruses that have been prevalent at the time, such as influenza and tuberculosis, were shown to be effectively inactivated by UV radiation [2,3]. For example, Wells had performed several initial experiments showing the germicidal effect of UV radiation in combating airborne infectious microorganisms as done by other researchers [4] [5]. His book, published in 1954, was one of the first comprehensive sources that described the characteristics of airborne infectious diseases and the effective usage of UV radiation [6].…”

Section: Introductionmentioning

confidence: 99%

Estimating the germicidal effect of upper-room UVGI system on exhaled air of patients based on ventilation efficiency

Sung

Kato

2011

Building and Environment

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a b s t r a c tUpper room (UR)-ultraviolet germicidal (UVGI) systems, one of several disinfection applications of UV, target airborne infectious diseases in rooms of buildings such as healthcare facilities. Previous studies have introduced many experiments showing the germicidal effect of UR-UVGI systems. In this study, a novel numerical method of estimating the germicidal effect of UR-UVGI systems for air exhaled by ward patients was introduced. The method adopts and modifies the concept of ventilation efficiency because the germicidal effect depends upon how the air containing airborne infectious particles flows and stays within UV-radiated area. A case study based on a four-patient ward showed that UV doses were correlated with the age of the air exhaled by a source patient, as expected. Moreover, the UV doses were considerably affected by the position of the UR-UVGI system. Inactivation rates of the influenza virus estimated using the UV doses, were in the range of 48e74%, and those of Mycobacterium tuberculosis were 68e90% in the breathing area of a neighboring patient. The results indicate not directly the decreased concentration of airborne infectious particles, but the possibility of inactivation caused by the UR-UVGI system, which is useful for system optimization.

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Section: Introductionmentioning

confidence: 99%

Estimating the germicidal effect of upper-room UVGI system on exhaled air of patients based on ventilation efficiency

Sung

Kato

2011

Building and Environment

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“…where E OL750,i,j (254 nm) is the 254 nm irradiance of lamp i measured by the OL750 at distance j , E meter,i,j (254 nm) is the 254 nm irradiance of lamp i measured by the meter at distance j , and C cos,i,j is the meter's cosine response correction factor given by (1) for lamp i at distance j . The responses of the detectors to wavelengths outside the UV-C region were studied by measuring the irradiance from the fluorescent and incandescent lamps at 20 cm.…”

Section: Spectral Response Measurementsmentioning

confidence: 99%

“…(1)(2)(3) UVGI lamps employ shortwave ultraviolet-C (UV-C, 100-280 nm) radiation to damage the DNA of microbes, such as bacteria and viruses, rendering them unable to replicate. (4) By inhibiting the growth of these agents, UVGI sources can help prevent the spread of disease in humans and animals.…”

Section: Introductionmentioning

confidence: 99%

Intercomparison of Instruments Used for Safety and Performance Measurements of Ultraviolet Germicidal Irradiation Lamps

Reed

Wengraitis

Sliney³

2009

Journal of Occupational and Environmental Hygiene

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Public health concerns such as multidrug-resistant tuberculosis, bioterrorism, pandemic influenza, and sick building syndrome have brought about increased interest in the use of ultraviolet germicidal irradiation (UVGI) to prevent the spread of airborne infection. UVGI lamps require that radiometric measurements be performed to ensure their safe and effective use. This study evaluates 10 detectors that measure the ultraviolet radiation hazard of low-pressure mercury UVGI lamps, including a polychromator spectroradiometer, narrowband detectors designed to measure the ultraviolet radiation in a short range of wavelengths, and broadband detectors with a varying spectral response designed to follow the UV hazard action spectrum. The angular responses, spectral responses, and linearity of the detectors were measured and compared. The agreement between the measured angular responses and the ideal cosine responses varied widely among the detectors, and in general, the detectors with diffusing optics agreed significantly better with the ideal cosine response. The spectral responses at 254 nm also varied widely among the detectors, and, in general, the narrowband detectors agreed more closely with the 254 nm irradiances measured under the same conditions by a double monochromator spectroradiometer. All detectors displayed good linearity. The angular and spectral response data were then used to develop correction factors for the effective irradiance measurements of two UVGI sources, each measured at 10, 20, and 30 cm. The measured effective irradiances were compared with those measured by a double monochromator spectroradiometer with an integrating sphere input optic. Prior to correction, the effective irradiances measured by the detectors varied widely, ranging from 0.29 to 2.7 times those measured by the spectroradiometer. The application of cosine and spectral response correction factors significantly improved the agreement for the effective irradiances measured by all of the detectors, typically to within 10-20%. Awareness of these detector characteristics can play a key role in ensuring the accuracy of health hazard measurements of UVGI lamps.

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“…(27) The effect of upper room UVGI has been successfully demonstrated in experimental room settings. (28)(29)(30)(31)(32)(33)(34)(35) Several epidemiological studies measured the ability of upper room UVGI to control the spread of airborne disease (e.g., measles) in the community with inconclusive results. (36)(37)(38)(39) No epidemiological studies on UV prevention of TB transmission in high-risk settings exist, but it is possible to develop a model that might provide insight into the question.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Tuberculosis Risk and Incidence under Upper Room Ultraviolet Germicidal Irradiation in a Waiting Room in a Hypothetical Scenario

Ko¹,

Burge²,

Nardell

et al. 2001

Risk Analysis

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Environmental control measures (ventilation, high-efficiency particulate air filtration, and upper room ultraviolet germicidal irradiation [UVGI]) are recommended to effectively control tuberculosis (TB) transmission from unsuspected TB patients in high-risk settings, but the effectiveness of their use is not often clear. This study presents a simulation model for a hypothetical hospital waiting room, in which the number of susceptible immunocompetent people in the waiting room follows a Poisson distribution (M = 5) in either low (annual number of TB patients = 5) or high TB risk settings (annual number of TB patients = 50), and used the model to evaluate the reduction of TB transmission risk by upper room UVGI. An exponential dose-response model was used for TB transmission and a two-zone model was used for evaluating the effect of upper room UVGI. Upper room UVGI reduced TB risk by 1.6-fold at 3 microW/cm2 UV irradiance in the upper room in the low TB risk setting and by 4.1-fold at 15 microW/cm2 UV irradiance in the upper room in the high TB risk setting. Use of upper room UVGI also reduced the mean annual new infection rate from 2.2 to 1.3 infections per year at 3 microW/cm2 and to 0.6 infections per year at 15 microW/cm2 in our hypothetical high-risk settings. The effect of upper room UVGI was sensitive to both vertical air velocity (air mixing) and UV irradiance level. Results from partitioning variability indicate that most variability of TB transmission risk came from waiting time in our hypothetical hospital.

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Viability of B. Coli Exposed to Ultra-Violet Radiation in Air

Cited by 55 publications

References 1 publication

Estimating the germicidal effect of upper-room UVGI system on exhaled air of patients based on ventilation efficiency

Estimating the germicidal effect of upper-room UVGI system on exhaled air of patients based on ventilation efficiency

Intercomparison of Instruments Used for Safety and Performance Measurements of Ultraviolet Germicidal Irradiation Lamps

Estimation of Tuberculosis Risk and Incidence under Upper Room Ultraviolet Germicidal Irradiation in a Waiting Room in a Hypothetical Scenario

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