CORD-19-Sentences  

CORD-19:9686d2f6d303d33768ba8cde093a9b3bf3be8481 JSONTXT 9 Projects

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Id Subject Object Predicate Lexical cue
TextSentencer_T1 0-90 Sentence denotes Applications of ultraviolet germicidal irradiation disinfection in health care facilities:
TextSentencer_T1 0-90 Sentence denotes Applications of ultraviolet germicidal irradiation disinfection in health care facilities:
TextSentencer_T2 91-140 Sentence denotes Effective adjunct, but not stand-alone technology
TextSentencer_T2 91-140 Sentence denotes Effective adjunct, but not stand-alone technology
TextSentencer_T3 142-150 Sentence denotes Abstract
TextSentencer_T3 142-150 Sentence denotes Abstract
TextSentencer_T4 151-311 Sentence denotes This review evaluates the applicability and relative contribution of ultraviolet germicidal irradiation (UVGI) to disinfection of air in health care facilities.
TextSentencer_T4 151-311 Sentence denotes This review evaluates the applicability and relative contribution of ultraviolet germicidal irradiation (UVGI) to disinfection of air in health care facilities.
TextSentencer_T5 312-393 Sentence denotes A section addressing the use of UVGI for environmental surfaces is also included.
TextSentencer_T5 312-393 Sentence denotes A section addressing the use of UVGI for environmental surfaces is also included.
TextSentencer_T6 394-516 Sentence denotes The germicidal susceptibility of biologic agents is addressed, but with emphasis on application in health care facilities.
TextSentencer_T6 394-516 Sentence denotes The germicidal susceptibility of biologic agents is addressed, but with emphasis on application in health care facilities.
TextSentencer_T7 517-919 Sentence denotes The balance of scientific evidence indicates that UVGI should be considered as a disinfection application in a health care setting only in conjunction with other well-established elements, such as appropriate heating, ventilating, and air-conditioning (HVAC) systems; dynamic removal of contaminants from the air; and preventive maintenance in combination with through cleaning of the care environment.
TextSentencer_T7 517-919 Sentence denotes The balance of scientific evidence indicates that UVGI should be considered as a disinfection application in a health care setting only in conjunction with other well-established elements, such as appropriate heating, ventilating, and air-conditioning (HVAC) systems; dynamic removal of contaminants from the air; and preventive maintenance in combination with through cleaning of the care environment.
TextSentencer_T8 920-1122 Sentence denotes We conclude that although UVGI is microbiocidal, it is not ''ready for prime time'' as a primary intervention to kill or inactivate infectious microorganisms; rather, it should be considered an adjunct.
TextSentencer_T8 920-1122 Sentence denotes We conclude that although UVGI is microbiocidal, it is not ''ready for prime time'' as a primary intervention to kill or inactivate infectious microorganisms; rather, it should be considered an adjunct.
TextSentencer_T9 1123-1464 Sentence denotes Other factors, such as careful design of the built environment, installation and effective operation of the HVAC system, and a high level of attention to traditional cleaning and disinfection, must be assessed before a health care facility can decide to rely solely on UVGI to meet indoor air quality requirements for health care facilities.
TextSentencer_T9 1123-1464 Sentence denotes Other factors, such as careful design of the built environment, installation and effective operation of the HVAC system, and a high level of attention to traditional cleaning and disinfection, must be assessed before a health care facility can decide to rely solely on UVGI to meet indoor air quality requirements for health care facilities.
TextSentencer_T10 1465-1732 Sentence denotes More targeted and multiparameter studies are needed to evaluate the efficacy, safety, and incremental benefit of UVGI for mitigating reservoirs of microorganisms and ultimately preventing cross-transmission of pathogens that lead to health care-associated infections.
TextSentencer_T10 1465-1732 Sentence denotes More targeted and multiparameter studies are needed to evaluate the efficacy, safety, and incremental benefit of UVGI for mitigating reservoirs of microorganisms and ultimately preventing cross-transmission of pathogens that lead to health care-associated infections.
TextSentencer_T11 1734-1871 Sentence denotes Ultraviolet germicidal irradiation (UVGI) has been used to ''scrub'' the air in health care facilities and laboratories for many decades.
TextSentencer_T11 1734-1871 Sentence denotes Ultraviolet germicidal irradiation (UVGI) has been used to ''scrub'' the air in health care facilities and laboratories for many decades.
TextSentencer_T12 1872-1987 Sentence denotes UVGI is known to be efficacious to varying degrees in controlling the circulation of airborne infectious particles.
TextSentencer_T12 1872-1987 Sentence denotes UVGI is known to be efficacious to varying degrees in controlling the circulation of airborne infectious particles.
TextSentencer_T13 1988-2083 Sentence denotes Approximately 60% of all UVGI air disinfection systems are installed in health care facilities.
TextSentencer_T13 1988-2083 Sentence denotes Approximately 60% of all UVGI air disinfection systems are installed in health care facilities.
TextSentencer_T14 2084-2175 Sentence denotes According to Kowalski and Bahnfleth, 1 this equates to 41% in hospitals and 19% in clinics.
TextSentencer_T14 2084-2175 Sentence denotes According to Kowalski and Bahnfleth, 1 this equates to 41% in hospitals and 19% in clinics.
TextSentencer_T15 2176-2283 Sentence denotes Until recently, most of the experimental data that led to the development of UVGI systems were decades old.
TextSentencer_T15 2176-2283 Sentence denotes Until recently, most of the experimental data that led to the development of UVGI systems were decades old.
TextSentencer_T16 2284-2416 Sentence denotes Aside from anecdotal observations, little information about the actual performance of these systems in hospital rooms was available.
TextSentencer_T16 2284-2416 Sentence denotes Aside from anecdotal observations, little information about the actual performance of these systems in hospital rooms was available.
TextSentencer_T17 2417-2734 Sentence denotes Although UV light is known to inactivate microorganisms, limiting their ability to grow and multiply when inhaled or picked up on surfaces, there is insufficient evidence on which to base a decision to rely solely on UVGI as an engineering control for preventing health care-associated tuberculosis (TB) transmission.
TextSentencer_T17 2417-2734 Sentence denotes Although UV light is known to inactivate microorganisms, limiting their ability to grow and multiply when inhaled or picked up on surfaces, there is insufficient evidence on which to base a decision to rely solely on UVGI as an engineering control for preventing health care-associated tuberculosis (TB) transmission.
TextSentencer_T18 2735-3017 Sentence denotes 2 Numerous laboratory studies, dating back to the 1930s, have been conducted to analyze the efficacy of UVGI for various microorganisms in a range of temperature and humidity conditions; few studies have evaluated the practical application of UVGI in health care buildings, however.
TextSentencer_T18 2735-3017 Sentence denotes 2 Numerous laboratory studies, dating back to the 1930s, have been conducted to analyze the efficacy of UVGI for various microorganisms in a range of temperature and humidity conditions; few studies have evaluated the practical application of UVGI in health care buildings, however.
TextSentencer_T19 3018-3124 Sentence denotes 3 Most of the existing evidence comes from laboratory investigations conducted under simulated conditions.
TextSentencer_T19 3018-3124 Sentence denotes 3 Most of the existing evidence comes from laboratory investigations conducted under simulated conditions.
TextSentencer_T20 3125-3246 Sentence denotes Our search revealed only one study that has been conducted in a physically realistic setting under controlled conditions.
TextSentencer_T20 3125-3246 Sentence denotes Our search revealed only one study that has been conducted in a physically realistic setting under controlled conditions.
TextSentencer_T21 3247-3474 Sentence denotes 4 That study served as the basis for the 2009 National Institute for Occupational Safety and Health (NIOSH) technical guidance document on the use of UVGI systems to protect health care providers from occupational TB infection.
TextSentencer_T21 3247-3474 Sentence denotes 4 That study served as the basis for the 2009 National Institute for Occupational Safety and Health (NIOSH) technical guidance document on the use of UVGI systems to protect health care providers from occupational TB infection.
TextSentencer_T22 3475-3633 Sentence denotes 5 This review examines the gaps in existing evidence and highlights design and operational factors that can significantly impact the efficacy of UVGI systems.
TextSentencer_T22 3475-3633 Sentence denotes 5 This review examines the gaps in existing evidence and highlights design and operational factors that can significantly impact the efficacy of UVGI systems.
TextSentencer_T23 3634-3821 Sentence denotes Myocobacterium tuberculosis, an obligate inhalational airborne pathogen, is inactivated by UVGI systems, which are most often are installed in the upper portion of rooms to disinfect air.
TextSentencer_T23 3634-3821 Sentence denotes Myocobacterium tuberculosis, an obligate inhalational airborne pathogen, is inactivated by UVGI systems, which are most often are installed in the upper portion of rooms to disinfect air.
TextSentencer_T24 3822-4043 Sentence denotes Today UVGI is receiving renewed interest, given the emergence of new infectious diseases such as pandemic strains of influenza, the ongoing threat of bioterrorism, and increased controls for aerosol-generating procedures.
TextSentencer_T24 3822-4043 Sentence denotes Today UVGI is receiving renewed interest, given the emergence of new infectious diseases such as pandemic strains of influenza, the ongoing threat of bioterrorism, and increased controls for aerosol-generating procedures.
TextSentencer_T25 4044-4147 Sentence denotes 6 In addition, highly drug-resistant strains of M tuberculosis have been reported in several countries.
TextSentencer_T25 4044-4147 Sentence denotes 6 In addition, highly drug-resistant strains of M tuberculosis have been reported in several countries.
TextSentencer_T26 4148-4580 Sentence denotes 7 Others have also highlighted problems from pathogens known to survive in the environment, such as multidrugresistant Acinobacter baumannii, Clostridium difficile, and others, which are increasingly the cause of invasive infections and outbreaks in a various settings. [8] [9] [10] [11] [12] Four technological methods can be used to reduce the risk of airborne transmission: pressurization, dilution, filtration, and purification.
TextSentencer_T26 4148-4580 Sentence denotes 7 Others have also highlighted problems from pathogens known to survive in the environment, such as multidrugresistant Acinobacter baumannii, Clostridium difficile, and others, which are increasingly the cause of invasive infections and outbreaks in a various settings. [8] [9] [10] [11] [12] Four technological methods can be used to reduce the risk of airborne transmission: pressurization, dilution, filtration, and purification.
TextSentencer_T27 4581-4590 Sentence denotes Pressure.
TextSentencer_T27 4581-4590 Sentence denotes Pressure.
TextSentencer_T28 4591-4727 Sentence denotes Differential pressurization refers to measurable differences in air pressure that creates a directional airflow between adjacent spaces.
TextSentencer_T28 4591-4727 Sentence denotes Differential pressurization refers to measurable differences in air pressure that creates a directional airflow between adjacent spaces.
TextSentencer_T29 4728-4884 Sentence denotes For example, airflow into airborne infection isolation rooms (AIIRs) ensures that the rooms are negative with respect to adjacent spaces, such as corridors.
TextSentencer_T29 4728-4884 Sentence denotes For example, airflow into airborne infection isolation rooms (AIIRs) ensures that the rooms are negative with respect to adjacent spaces, such as corridors.
TextSentencer_T30 4885-5132 Sentence denotes Positive pressure, or airflow out of a defined space, is also common in facilities, used to mitigate the entrance of contaminants from adjacent areas into spaces in which invasive procedures are performed, such as an operating and procedure rooms.
TextSentencer_T30 4885-5132 Sentence denotes Positive pressure, or airflow out of a defined space, is also common in facilities, used to mitigate the entrance of contaminants from adjacent areas into spaces in which invasive procedures are performed, such as an operating and procedure rooms.
TextSentencer_T31 5133-5142 Sentence denotes Dilution.
TextSentencer_T31 5133-5142 Sentence denotes Dilution.
TextSentencer_T32 5143-5267 Sentence denotes High ventilation rates, in terms of high values of air changes/hour (ACH), control particles by removal through ventilation.
TextSentencer_T32 5143-5267 Sentence denotes High ventilation rates, in terms of high values of air changes/hour (ACH), control particles by removal through ventilation.
TextSentencer_T33 5268-5394 Sentence denotes Current guidelines suggest a value of 12 ACH for new facilities when designing an AIIR, with 6 ACH the absolute minimum value.
TextSentencer_T33 5268-5394 Sentence denotes Current guidelines suggest a value of 12 ACH for new facilities when designing an AIIR, with 6 ACH the absolute minimum value.
TextSentencer_T34 5395-5638 Sentence denotes The trade-off with this means of control is that increasing the ventilation rate results in diminishing returns in terms of removal; that is, there is increased removal of particulates with ACH .12, but at a cost of greater energy consumption.
TextSentencer_T34 5395-5638 Sentence denotes The trade-off with this means of control is that increasing the ventilation rate results in diminishing returns in terms of removal; that is, there is increased removal of particulates with ACH .12, but at a cost of greater energy consumption.
TextSentencer_T35 5639-5751 Sentence denotes Thus, the incremental benefit to prevent cross-transmission is much more difficult to demonstrate beyond 12 ACH.
TextSentencer_T35 5639-5751 Sentence denotes Thus, the incremental benefit to prevent cross-transmission is much more difficult to demonstrate beyond 12 ACH.
TextSentencer_T36 5752-5832 Sentence denotes For other spaces, such as operating rooms, national guidelines recommend 20 ACH.
TextSentencer_T36 5752-5832 Sentence denotes For other spaces, such as operating rooms, national guidelines recommend 20 ACH.
TextSentencer_T37 5833-5844 Sentence denotes Filtration.
TextSentencer_T37 5833-5844 Sentence denotes Filtration.
TextSentencer_T38 5845-5935 Sentence denotes Filters are a key element of air-handling units (AHUs) that supply air to occupied spaces.
TextSentencer_T38 5845-5935 Sentence denotes Filters are a key element of air-handling units (AHUs) that supply air to occupied spaces.
TextSentencer_T39 5936-6166 Sentence denotes There are two banks of filters: a prefilter of approximately 30% particle removal efficiency (defined in terms of a minimum efficiency reporting value [MERV] as MERV 7), followed by a final filter of 90%-95% efficiency (MERV 14) .
TextSentencer_T39 5936-6166 Sentence denotes There are two banks of filters: a prefilter of approximately 30% particle removal efficiency (defined in terms of a minimum efficiency reporting value [MERV] as MERV 7), followed by a final filter of 90%-95% efficiency (MERV 14) .
TextSentencer_T40 6167-6354 Sentence denotes High-efficiency particulate air (HEPA) filtration can be used to supplement other recommended ventilation measures by providing a minimum removal efficiency of 99.97% of 0.3-mm particles.
TextSentencer_T40 6167-6354 Sentence denotes High-efficiency particulate air (HEPA) filtration can be used to supplement other recommended ventilation measures by providing a minimum removal efficiency of 99.97% of 0.3-mm particles.
TextSentencer_T41 6355-6474 Sentence denotes HEPA filters are typically used in ventilation systems that recirculate the air from an AIIR or from a portable device.
TextSentencer_T41 6355-6474 Sentence denotes HEPA filters are typically used in ventilation systems that recirculate the air from an AIIR or from a portable device.
TextSentencer_T42 6475-6654 Sentence denotes HEPA filters also are used to filter special care areas for highly immunocompromised patients, such as a protective environment room as part of a bone marrow transplantation unit.
TextSentencer_T42 6475-6654 Sentence denotes HEPA filters also are used to filter special care areas for highly immunocompromised patients, such as a protective environment room as part of a bone marrow transplantation unit.
TextSentencer_T43 6655-6737 Sentence denotes Proper installation, maintenance, and monitoring of the HEPA filters is essential.
TextSentencer_T43 6655-6737 Sentence denotes Proper installation, maintenance, and monitoring of the HEPA filters is essential.
TextSentencer_T44 6738-6751 Sentence denotes Purification.
TextSentencer_T44 6738-6751 Sentence denotes Purification.
TextSentencer_T45 6752-6978 Sentence denotes Purifying the air through UVGI destroys the infectious agents in the air through exposure to ultraviolet (UV) radiation, which damages the nucleic acid of bacteria and viruses, including M tuberculosis, preventing replication.
TextSentencer_T45 6752-6978 Sentence denotes Purifying the air through UVGI destroys the infectious agents in the air through exposure to ultraviolet (UV) radiation, which damages the nucleic acid of bacteria and viruses, including M tuberculosis, preventing replication.
TextSentencer_T46 6979-7080 Sentence denotes 13 For spores, UV-C exposure is postulated to result in the formation of lethal photoactive products.
TextSentencer_T46 6979-7080 Sentence denotes 13 For spores, UV-C exposure is postulated to result in the formation of lethal photoactive products.
TextSentencer_T47 7081-7226 Sentence denotes Airborne transmission of infectious agents involves droplets that are expelled by sneezing or coughing or are otherwise distributed into the air.
TextSentencer_T47 7081-7226 Sentence denotes Airborne transmission of infectious agents involves droplets that are expelled by sneezing or coughing or are otherwise distributed into the air.
TextSentencer_T48 7227-7653 Sentence denotes Although the liquid/vapor around the infectious agent evaporates, the residue (or droplet nuclei) may remain in the air for long periods, depending on such factors as particle size, velocity, force of expulsion, particle density, infectivity (ie, viability of the microorganism when exposed to the environment and its ability to cause infection when a susceptible host is subsequently exposed), humidity, and rate of air flow.
TextSentencer_T48 7227-7653 Sentence denotes Although the liquid/vapor around the infectious agent evaporates, the residue (or droplet nuclei) may remain in the air for long periods, depending on such factors as particle size, velocity, force of expulsion, particle density, infectivity (ie, viability of the microorganism when exposed to the environment and its ability to cause infection when a susceptible host is subsequently exposed), humidity, and rate of air flow.
TextSentencer_T49 7654-7814 Sentence denotes Roy and Milton 14 suggested that transmission of infectious agents does not correlate solely with the size of the microbes in droplet nuclei or larger droplets.
TextSentencer_T49 7654-7814 Sentence denotes Roy and Milton 14 suggested that transmission of infectious agents does not correlate solely with the size of the microbes in droplet nuclei or larger droplets.
TextSentencer_T50 7815-8215 Sentence denotes The size can range from obligate inhalational airborne pathogens, such as M tuberculosis, to preferential inhalational transmission, such as measles virus or varicella-zoster (VZV) (based on the ability to cause infection in distal airways), to opportunistic pathogens like SARS-CoV that take advantage of unique environmental and clinical circumstances that permit dissemination over several meters.
TextSentencer_T50 7815-8215 Sentence denotes The size can range from obligate inhalational airborne pathogens, such as M tuberculosis, to preferential inhalational transmission, such as measles virus or varicella-zoster (VZV) (based on the ability to cause infection in distal airways), to opportunistic pathogens like SARS-CoV that take advantage of unique environmental and clinical circumstances that permit dissemination over several meters.
TextSentencer_T51 8216-8421 Sentence denotes For M tuberculosis, the prototype obligate inhalational pathogen, airborne droplet nuclei containing this agent can travel via air currents, aided by the ventilation system, and be spread over a wide area.
TextSentencer_T51 8216-8421 Sentence denotes For M tuberculosis, the prototype obligate inhalational pathogen, airborne droplet nuclei containing this agent can travel via air currents, aided by the ventilation system, and be spread over a wide area.
TextSentencer_T52 8422-8532 Sentence denotes The disease-causing organisms then are inhaled and cause infection. induction of cough by chest physiotherapy.
TextSentencer_T52 8422-8532 Sentence denotes The disease-causing organisms then are inhaled and cause infection. induction of cough by chest physiotherapy.
TextSentencer_T53 8533-8721 Sentence denotes There is theoretical chance that pathogen-laden droplets expelled during these procedures might travel further distances and reach deeper into the respiratory tract of susceptible persons.
TextSentencer_T53 8533-8721 Sentence denotes There is theoretical chance that pathogen-laden droplets expelled during these procedures might travel further distances and reach deeper into the respiratory tract of susceptible persons.
TextSentencer_T54 8722-8937 Sentence denotes Concerns over the protection of health care personnel performing these types of procedures on patients with H1N1 2009 infection led to recommendations for higher facepiece filtering devices, such as N95 respirators.
TextSentencer_T54 8722-8937 Sentence denotes Concerns over the protection of health care personnel performing these types of procedures on patients with H1N1 2009 infection led to recommendations for higher facepiece filtering devices, such as N95 respirators.
TextSentencer_T55 8938-9068 Sentence denotes The latter have traditionally been required only to protect health care personnel against occupational exposure to M tuberculosis.
TextSentencer_T55 8938-9068 Sentence denotes The latter have traditionally been required only to protect health care personnel against occupational exposure to M tuberculosis.
TextSentencer_T56 9069-9181 Sentence denotes Droplet transmission involves relatively short-range movement of the infectious agent, over a distance of 1-2 m.
TextSentencer_T56 9069-9181 Sentence denotes Droplet transmission involves relatively short-range movement of the infectious agent, over a distance of 1-2 m.
TextSentencer_T57 9182-9280 Sentence denotes Some of these agents (eg, influenza virus) also can be transmitted by direct and indirect contact.
TextSentencer_T57 9182-9280 Sentence denotes Some of these agents (eg, influenza virus) also can be transmitted by direct and indirect contact.
TextSentencer_T58 9281-9519 Sentence denotes With droplet transmission, respiratory droplets containing infectious pathogens travel directly from the respiratory tract of the infectious individual to another susceptible person through deposition on mucosal surfaces of the recipient.
TextSentencer_T58 9281-9519 Sentence denotes With droplet transmission, respiratory droplets containing infectious pathogens travel directly from the respiratory tract of the infectious individual to another susceptible person through deposition on mucosal surfaces of the recipient.
TextSentencer_T59 9520-9823 Sentence denotes The distance that droplets travel depends on the velocity and mechanism by which respiratory droplets are propelled from the source, the density of respiratory secretions, environmental factors such as temperature and humidity, and the ability of the pathogen to maintain infectivity over that distance.
TextSentencer_T59 9520-9823 Sentence denotes The distance that droplets travel depends on the velocity and mechanism by which respiratory droplets are propelled from the source, the density of respiratory secretions, environmental factors such as temperature and humidity, and the ability of the pathogen to maintain infectivity over that distance.
TextSentencer_T60 9824-9914 Sentence denotes Droplets in dry air evaporate quickly, shrink in size, and fall to the ground more slowly.
TextSentencer_T60 9824-9914 Sentence denotes Droplets in dry air evaporate quickly, shrink in size, and fall to the ground more slowly.
TextSentencer_T61 9915-10017 Sentence denotes The changing size of a droplet affects how it responds to airflow patterns and how quickly it settles.
TextSentencer_T61 9915-10017 Sentence denotes The changing size of a droplet affects how it responds to airflow patterns and how quickly it settles.
TextSentencer_T62 10018-10225 Sentence denotes Small pressure differences, induced by natural forces such as thermal buoyancy due to air temperature differences, the wind, or mechanical fans, can generate air flows that move air from one room to another.
TextSentencer_T62 10018-10225 Sentence denotes Small pressure differences, induced by natural forces such as thermal buoyancy due to air temperature differences, the wind, or mechanical fans, can generate air flows that move air from one room to another.
TextSentencer_T63 10226-10311 Sentence denotes Air filtration aims to reduce airborne concentrations to well below infectious doses.
TextSentencer_T63 10226-10311 Sentence denotes Air filtration aims to reduce airborne concentrations to well below infectious doses.
TextSentencer_T64 10312-10372 Sentence denotes In a hospital setting, patients lie in bed much of the time.
TextSentencer_T64 10312-10372 Sentence denotes In a hospital setting, patients lie in bed much of the time.
TextSentencer_T65 10373-10516 Sentence denotes The direction of an exhalation jet from a standing or seated person and that from a lying person can be different (eg, the latter may face up).
TextSentencer_T65 10373-10516 Sentence denotes The direction of an exhalation jet from a standing or seated person and that from a lying person can be different (eg, the latter may face up).
TextSentencer_T66 10517-10638 Sentence denotes The upward thermal plume generated by a standing or seated person is much stronger than that generated by a lying person.
TextSentencer_T66 10517-10638 Sentence denotes The upward thermal plume generated by a standing or seated person is much stronger than that generated by a lying person.
TextSentencer_T67 10639-10758 Sentence denotes Thus, some differences between the behaviors of breathing flows in hospital and other indoor environments are expected.
TextSentencer_T67 10639-10758 Sentence denotes Thus, some differences between the behaviors of breathing flows in hospital and other indoor environments are expected.
TextSentencer_T68 10759-11011 Sentence denotes The exhalation jet from a lying patient can behave differently in different ventilation systems, and also can be affected by other factors, such as the mode of contaminant release and the thermal plume generated by the human body or other heat sources.
TextSentencer_T68 10759-11011 Sentence denotes The exhalation jet from a lying patient can behave differently in different ventilation systems, and also can be affected by other factors, such as the mode of contaminant release and the thermal plume generated by the human body or other heat sources.
TextSentencer_T69 11012-11231 Sentence denotes Understanding breathing flows from a patient lying supine with different ventilation systems is useful for developing an effective ventilation method for minimizing the risk of cross-infection via airborne transmission.
TextSentencer_T69 11012-11231 Sentence denotes Understanding breathing flows from a patient lying supine with different ventilation systems is useful for developing an effective ventilation method for minimizing the risk of cross-infection via airborne transmission.
TextSentencer_T70 11232-11425 Sentence denotes Droplet nuclei ,5 mm in diameter exhibit a settling velocity of ,1 m/h (88 feet per minute in still air, and can follow the exhalation flows as well as the ambient air flows in a hospital ward.
TextSentencer_T70 11232-11425 Sentence denotes Droplet nuclei ,5 mm in diameter exhibit a settling velocity of ,1 m/h (88 feet per minute in still air, and can follow the exhalation flows as well as the ambient air flows in a hospital ward.
TextSentencer_T71 11426-11669 Sentence denotes Clinically applicable distinctions are made between short-range airborne infection routes (between individuals, generally ,1 m apart) and long-range routes (within a room, between rooms, or between distant locations, generally distances .1 m).
TextSentencer_T71 11426-11669 Sentence denotes Clinically applicable distinctions are made between short-range airborne infection routes (between individuals, generally ,1 m apart) and long-range routes (within a room, between rooms, or between distant locations, generally distances .1 m).
TextSentencer_T72 11670-11919 Sentence denotes Fennelly et al 15 Small droplets also may participate in short-range transmission, but they are more likely than larger droplets to evaporate to become droplet nuclei and then be considered to have the potential for long-range airborne transmission.
TextSentencer_T72 11670-11919 Sentence denotes Fennelly et al 15 Small droplets also may participate in short-range transmission, but they are more likely than larger droplets to evaporate to become droplet nuclei and then be considered to have the potential for long-range airborne transmission.
TextSentencer_T73 11920-12119 Sentence denotes True long-range aerosol transmission becomes possible when the droplets of infectious material are sufficiently small to remain airborne almost indefinitely and to be transmitted over long distances.
TextSentencer_T73 11920-12119 Sentence denotes True long-range aerosol transmission becomes possible when the droplets of infectious material are sufficiently small to remain airborne almost indefinitely and to be transmitted over long distances.
TextSentencer_T74 12120-12237 Sentence denotes Pathogens that are not transmitted routinely by the droplet route can be dispersed into the air over short distances.
TextSentencer_T74 12120-12237 Sentence denotes Pathogens that are not transmitted routinely by the droplet route can be dispersed into the air over short distances.
TextSentencer_T75 12238-12624 Sentence denotes For example, as reported by Bassetti et al, 17 although Staphylococcus aureus is most commonly transmitted by the contact route, viral upper respiratory tract infection has been associated with increased dispersal of S aureus from the nose into the air over a distance of 4 feet under both outbreak and experimental conditions, known as the ''cloud baby'' and ''cloud adult'' phenomena.
TextSentencer_T75 12238-12624 Sentence denotes For example, as reported by Bassetti et al, 17 although Staphylococcus aureus is most commonly transmitted by the contact route, viral upper respiratory tract infection has been associated with increased dispersal of S aureus from the nose into the air over a distance of 4 feet under both outbreak and experimental conditions, known as the ''cloud baby'' and ''cloud adult'' phenomena.
TextSentencer_T76 12625-12773 Sentence denotes Once infectious droplets are released, the main factors that determine how they move are their size and the airflow patterns that carry them around.
TextSentencer_T76 12625-12773 Sentence denotes Once infectious droplets are released, the main factors that determine how they move are their size and the airflow patterns that carry them around.
TextSentencer_T77 12774-12848 Sentence denotes Droplet size changes with time, depending on the environmental conditions.
TextSentencer_T77 12774-12848 Sentence denotes Droplet size changes with time, depending on the environmental conditions.
TextSentencer_T78 12849-12939 Sentence denotes Droplets in dry air evaporate quickly, shrink in size, and fall to the ground more slowly.
TextSentencer_T78 12849-12939 Sentence denotes Droplets in dry air evaporate quickly, shrink in size, and fall to the ground more slowly.
TextSentencer_T79 12940-13042 Sentence denotes The changing size of a droplet affects how it responds to airflow patterns and how quickly it settles.
TextSentencer_T79 12940-13042 Sentence denotes The changing size of a droplet affects how it responds to airflow patterns and how quickly it settles.
TextSentencer_T80 13043-13183 Sentence denotes Movement of people in a room plays a significant part in disturbing airflow and also in transporting infected air from one place to another.
TextSentencer_T80 13043-13183 Sentence denotes Movement of people in a room plays a significant part in disturbing airflow and also in transporting infected air from one place to another.
TextSentencer_T81 13184-13268 Sentence denotes Thus, room airflow is governed primarily, but not solely, by mechanical ventilation.
TextSentencer_T81 13184-13268 Sentence denotes Thus, room airflow is governed primarily, but not solely, by mechanical ventilation.
TextSentencer_T82 13269-13367 Sentence denotes Other influences include temperature, humidity, movement of personnel and patients, and equipment.
TextSentencer_T82 13269-13367 Sentence denotes Other influences include temperature, humidity, movement of personnel and patients, and equipment.
TextSentencer_T83 13368-13560 Sentence denotes The varying combinations of these factors make the route and suspension time of an infectious particle very difficult to predict in a dynamic, real-world environment of a health care facility.
TextSentencer_T83 13368-13560 Sentence denotes The varying combinations of these factors make the route and suspension time of an infectious particle very difficult to predict in a dynamic, real-world environment of a health care facility.
TextSentencer_T84 13561-13696 Sentence denotes Measles and chickenpox (VZV) are both lipidenveloped and sensitive to changes in temperature, relative humidity (RH), and UV radiation.
TextSentencer_T84 13561-13696 Sentence denotes Measles and chickenpox (VZV) are both lipidenveloped and sensitive to changes in temperature, relative humidity (RH), and UV radiation.
TextSentencer_T85 13697-14261 Sentence denotes According to Cox, 18 Stephenson et al, 19 and Ijaz et al, 20 viruses without a lipid envelope (eg, poliovirus) generally survive longer at high RH (.50%), but lipid-enveloped viruses (eg, influenza, Lassa fever virus, human coronavirus [hCV] 229E) survive longer in low RH (,50%). [18] [19] [20] Data on hCV 229E indicate that when airborne, this virus has a survival half-life of about 3 hours at an RH of 80%, 67 hours at an RH of 50%, and 27 hours at an RH of 30% at 20 8C, suggesting that high RH (.80%) is most detrimental to the survival of this coronavirus.
TextSentencer_T85 13697-14261 Sentence denotes According to Cox, 18 Stephenson et al, 19 and Ijaz et al, 20 viruses without a lipid envelope (eg, poliovirus) generally survive longer at high RH (.50%), but lipid-enveloped viruses (eg, influenza, Lassa fever virus, human coronavirus [hCV] 229E) survive longer in low RH (,50%). [18] [19] [20] Data on hCV 229E indicate that when airborne, this virus has a survival half-life of about 3 hours at an RH of 80%, 67 hours at an RH of 50%, and 27 hours at an RH of 30% at 20 8C, suggesting that high RH (.80%) is most detrimental to the survival of this coronavirus.
TextSentencer_T86 14262-14451 Sentence denotes Bean et al 21 reported that influenza can survive for 24-48 hours on hard, nonporous surfaces such as stainless steel and plastic, but for less than 8-12 hours on cloth, paper, and tissues.
TextSentencer_T86 14262-14451 Sentence denotes Bean et al 21 reported that influenza can survive for 24-48 hours on hard, nonporous surfaces such as stainless steel and plastic, but for less than 8-12 hours on cloth, paper, and tissues.
TextSentencer_T87 14452-14630 Sentence denotes In addition, influenza virus can survive for up to 5 minutes on hands, and can be transferred to hands from these nonporous surfaces for 24 hours and from tissues for 15 minutes.
TextSentencer_T87 14452-14630 Sentence denotes In addition, influenza virus can survive for up to 5 minutes on hands, and can be transferred to hands from these nonporous surfaces for 24 hours and from tissues for 15 minutes.
TextSentencer_T88 14631-14838 Sentence denotes 21 More recently, Lai et al 22 demonstrated that SARS CoV can survive in alkaline diarrhea stools for up to 4 days and can remain infectious in respiratory specimens for more than 7 days at room temperature.
TextSentencer_T88 14631-14838 Sentence denotes 21 More recently, Lai et al 22 demonstrated that SARS CoV can survive in alkaline diarrhea stools for up to 4 days and can remain infectious in respiratory specimens for more than 7 days at room temperature.
TextSentencer_T89 14839-15131 Sentence denotes Similarities with other viruses of nosocomial importance (eg, other RNA lipid-enveloped respiratory viruses, such as influenza) suggest that such organisms can survive long enough in aerosols to cause disease, especially when associated with biological fluids such as mucus, feces, and blood.
TextSentencer_T89 14839-15131 Sentence denotes Similarities with other viruses of nosocomial importance (eg, other RNA lipid-enveloped respiratory viruses, such as influenza) suggest that such organisms can survive long enough in aerosols to cause disease, especially when associated with biological fluids such as mucus, feces, and blood.
TextSentencer_T90 15132-15242 Sentence denotes This sensitivity to environmental conditions also might help explain the seasonality of some viral infections.
TextSentencer_T90 15132-15242 Sentence denotes This sensitivity to environmental conditions also might help explain the seasonality of some viral infections.
TextSentencer_T91 15243-15434 Sentence denotes Regarding influenza transmission, Brankston et al 23 concluded that natural influenza transmission in humans occurs via droplets and contact over short distances as opposed to long distances.
TextSentencer_T91 15243-15434 Sentence denotes Regarding influenza transmission, Brankston et al 23 concluded that natural influenza transmission in humans occurs via droplets and contact over short distances as opposed to long distances.
TextSentencer_T92 15435-15750 Sentence denotes Although none of the studies that they reviewed could specifically rule out airborne transmission, the authors believed that the airborne route is neither the predominant mode of transmission nor a frequent enough occurrence to be of significant concern when considering control measures for most clinical settings.
TextSentencer_T92 15435-15750 Sentence denotes Although none of the studies that they reviewed could specifically rule out airborne transmission, the authors believed that the airborne route is neither the predominant mode of transmission nor a frequent enough occurrence to be of significant concern when considering control measures for most clinical settings.
TextSentencer_T93 15751-15819 Sentence denotes 23 A recent epidemiologic investigation confirmed their conclusions.
TextSentencer_T93 15751-15819 Sentence denotes 23 A recent epidemiologic investigation confirmed their conclusions.
TextSentencer_T94 15820-15822 Sentence denotes 24
TextSentencer_T94 15820-15822 Sentence denotes 24
TextSentencer_T95 15824-15982 Sentence denotes A recent systematic review by Li et al 25 demonstrated that adequate or inadequate ventilation has an effect on the risk of infection via infectious aerosols.
TextSentencer_T95 15824-15982 Sentence denotes A recent systematic review by Li et al 25 demonstrated that adequate or inadequate ventilation has an effect on the risk of infection via infectious aerosols.
TextSentencer_T96 15983-16192 Sentence denotes An inefficient ventilation system causes the spread of airborne disease, whereas an efficient ventilation system can help mitigate the spread of infectious particles and thereby reduce transmission of disease.
TextSentencer_T96 15983-16192 Sentence denotes An inefficient ventilation system causes the spread of airborne disease, whereas an efficient ventilation system can help mitigate the spread of infectious particles and thereby reduce transmission of disease.
TextSentencer_T97 16193-16371 Sentence denotes 25 Even before the 2003 SARS epidemic, there was strong evidence that ventilation and building finishes are important determinants of the nosocomial transmission of tuberculosis.
TextSentencer_T97 16193-16371 Sentence denotes 25 Even before the 2003 SARS epidemic, there was strong evidence that ventilation and building finishes are important determinants of the nosocomial transmission of tuberculosis.
TextSentencer_T98 16372-16628 Sentence denotes According to the Centers for Disease Control and Prevention's (CDC) Guidelines for Environmental Infection Control in Health-Care Facilities, only TB, measles (rubeola virus), and chickenpox (VZV) should be considered ''true'' airborne infectious diseases.
TextSentencer_T98 16372-16628 Sentence denotes According to the Centers for Disease Control and Prevention's (CDC) Guidelines for Environmental Infection Control in Health-Care Facilities, only TB, measles (rubeola virus), and chickenpox (VZV) should be considered ''true'' airborne infectious diseases.
TextSentencer_T99 16629-16824 Sentence denotes 26 However, other infectious agents, such as SARS CoV, are sometimes called ''opportunistic,'' because they might be transmissible over short distances (eg, 1-2 m), given a favorable environment.
TextSentencer_T99 16629-16824 Sentence denotes 26 However, other infectious agents, such as SARS CoV, are sometimes called ''opportunistic,'' because they might be transmissible over short distances (eg, 1-2 m), given a favorable environment.
TextSentencer_T100 16825-16827 Sentence denotes 14
TextSentencer_T100 16825-16827 Sentence denotes 14
TextSentencer_T101 16829-16999 Sentence denotes All viruses and almost all bacteria (excluding spores) are vulnerable to moderate levels of UVGI exposure, but the magnitude of the effect is extremely species-dependent.
TextSentencer_T101 16829-16999 Sentence denotes All viruses and almost all bacteria (excluding spores) are vulnerable to moderate levels of UVGI exposure, but the magnitude of the effect is extremely species-dependent.
TextSentencer_T102 17000-17154 Sentence denotes 27 Spores, which are larger and more resistant to UVGI than most bacteria, can be effectively removed through high-efficiency air filtration without UVGI.
TextSentencer_T102 17000-17154 Sentence denotes 27 Spores, which are larger and more resistant to UVGI than most bacteria, can be effectively removed through high-efficiency air filtration without UVGI.
TextSentencer_T103 17155-17234 Sentence denotes Some UGVI systems are installed in conjunction with high-efficiency filtration.
TextSentencer_T103 17155-17234 Sentence denotes Some UGVI systems are installed in conjunction with high-efficiency filtration.
TextSentencer_T104 17235-17329 Sentence denotes This combination design can be very effective against biological agents in certain situations.
TextSentencer_T104 17235-17329 Sentence denotes This combination design can be very effective against biological agents in certain situations.
TextSentencer_T105 17330-17398 Sentence denotes Smaller microbes that are difficult to 38 Reprinted with permission.
TextSentencer_T105 17330-17398 Sentence denotes Smaller microbes that are difficult to 38 Reprinted with permission.
TextSentencer_T106 17399-17565 Sentence denotes 5 filter out tend to be more susceptible to UVGI, whereas larger microbes, such as spores, which are more resistant to UVGI, tend to be easier to filter out (Fig 1) .
TextSentencer_T106 17399-17565 Sentence denotes 5 filter out tend to be more susceptible to UVGI, whereas larger microbes, such as spores, which are more resistant to UVGI, tend to be easier to filter out (Fig 1) .
TextSentencer_T107 17566-17774 Sentence denotes 29 A recent Taiwanese study found that the effectiveness of UVGI depends strongly on the type of virus nucleic acid, and that viruses with dsRNA or dsDNA are significantly less susceptible to UV inactivation.
TextSentencer_T107 17566-17774 Sentence denotes 29 A recent Taiwanese study found that the effectiveness of UVGI depends strongly on the type of virus nucleic acid, and that viruses with dsRNA or dsDNA are significantly less susceptible to UV inactivation.
TextSentencer_T108 17775-17922 Sentence denotes 30 For 90% airborne virus inactivation, the UVGI dose was approximately 2-fold higher for dsRNA and dsDNA viruses than for ssRNA and ssDNA viruses.
TextSentencer_T108 17775-17922 Sentence denotes 30 For 90% airborne virus inactivation, the UVGI dose was approximately 2-fold higher for dsRNA and dsDNA viruses than for ssRNA and ssDNA viruses.
TextSentencer_T109 17923-18107 Sentence denotes The microorganism susceptibility factor was the highest for the viruses, similar to that for fragile bacteria, but 13-20 times higher than that for endospore bacteria or fungal spores.
TextSentencer_T109 17923-18107 Sentence denotes The microorganism susceptibility factor was the highest for the viruses, similar to that for fragile bacteria, but 13-20 times higher than that for endospore bacteria or fungal spores.
TextSentencer_T110 18108-18326 Sentence denotes The susceptibility factor for the viruses was higher at 55% RH than that at 85% RH, possibly because under high RH, water adsorption onto the virus surface might provide protection against UV-induced DNA or RNA damage.
TextSentencer_T110 18108-18326 Sentence denotes The susceptibility factor for the viruses was higher at 55% RH than that at 85% RH, possibly because under high RH, water adsorption onto the virus surface might provide protection against UV-induced DNA or RNA damage.
TextSentencer_T111 18327-18329 Sentence denotes 30
TextSentencer_T111 18327-18329 Sentence denotes 30
TextSentencer_T112 18331-18498 Sentence denotes Supplemental control UVGI has been used as a supplement to mechanical ventilation to inactivate airborne infectious agents to protect the health of building occupants.
TextSentencer_T112 18331-18498 Sentence denotes Supplemental control UVGI has been used as a supplement to mechanical ventilation to inactivate airborne infectious agents to protect the health of building occupants.
TextSentencer_T113 18499-18637 Sentence denotes Upper-room UVGI installations are frequently used to provide ACH equivalent or effective (e-ACH) to that recommended by the CDC for AIIRs.
TextSentencer_T113 18499-18637 Sentence denotes Upper-room UVGI installations are frequently used to provide ACH equivalent or effective (e-ACH) to that recommended by the CDC for AIIRs.
TextSentencer_T114 18638-18760 Sentence denotes However e-ACH is not acceptable for meeting CDC recommendations as a primary environmental control against M tuberculosis.
TextSentencer_T114 18638-18760 Sentence denotes However e-ACH is not acceptable for meeting CDC recommendations as a primary environmental control against M tuberculosis.
TextSentencer_T115 18761-18821 Sentence denotes UVGI generally refers to a UV wavelength of 253.7 nm (UV-C).
TextSentencer_T115 18761-18821 Sentence denotes UVGI generally refers to a UV wavelength of 253.7 nm (UV-C).
TextSentencer_T116 18822-18987 Sentence denotes Exposure to UV light at this wavelength is a practical and cost-effective method of inactivating airborne viruses, mycoplasma, bacteria, and fungi on clean surfaces.
TextSentencer_T116 18822-18987 Sentence denotes Exposure to UV light at this wavelength is a practical and cost-effective method of inactivating airborne viruses, mycoplasma, bacteria, and fungi on clean surfaces.
TextSentencer_T117 18988-18990 Sentence denotes 31
TextSentencer_T117 18988-18990 Sentence denotes 31
TextSentencer_T118 18991-19175 Sentence denotes The most widely used application of UVGI is in the form of passive upper-room fixtures containing UVGI lamps that provide a horizontal layer of UV energy field above the occupied zone.
TextSentencer_T118 18991-19175 Sentence denotes The most widely used application of UVGI is in the form of passive upper-room fixtures containing UVGI lamps that provide a horizontal layer of UV energy field above the occupied zone.
TextSentencer_T119 19176-19368 Sentence denotes These fixtures are designed to inactivate bacteria that enter the upper irradiated zone, and their efficacy is highly reliant on, among other factors, the airflow field conditions in the room.
TextSentencer_T119 19176-19368 Sentence denotes These fixtures are designed to inactivate bacteria that enter the upper irradiated zone, and their efficacy is highly reliant on, among other factors, the airflow field conditions in the room.
TextSentencer_T120 19369-19546 Sentence denotes The survival probability of bacteria exposed to UV irradiance depends on the susceptibility of the target microorganism and the dose and duration of UV-C to which it is exposed.
TextSentencer_T120 19369-19546 Sentence denotes The survival probability of bacteria exposed to UV irradiance depends on the susceptibility of the target microorganism and the dose and duration of UV-C to which it is exposed.
TextSentencer_T121 19547-19693 Sentence denotes 32 Lamps used to produce UV-C are located relatively high up in the room (8 ft), to prevent exposure to occupants by a specially designed fixture.
TextSentencer_T121 19547-19693 Sentence denotes 32 Lamps used to produce UV-C are located relatively high up in the room (8 ft), to prevent exposure to occupants by a specially designed fixture.
TextSentencer_T122 19694-19988 Sentence denotes There are two basic designs: a ''pan'' fixture with UVGI unshielded above the unit to direct the irradiation upward, and a fixture with a series of parallel plates that direct the irradiation outward while preventing the light from reaching the eyes or unprotected skin of the room's occupants.
TextSentencer_T122 19694-19988 Sentence denotes There are two basic designs: a ''pan'' fixture with UVGI unshielded above the unit to direct the irradiation upward, and a fixture with a series of parallel plates that direct the irradiation outward while preventing the light from reaching the eyes or unprotected skin of the room's occupants.
TextSentencer_T123 19989-20125 Sentence denotes Germicidal activity is dependent on air mixing via convection between the room's irradiated upper zone and the lower patient care zones.
TextSentencer_T123 19989-20125 Sentence denotes Germicidal activity is dependent on air mixing via convection between the room's irradiated upper zone and the lower patient care zones.
TextSentencer_T124 20126-20308 Sentence denotes 32 This was confirmed in an investigation by Miller et al 4 that involved installation of upper-room UVGI units and evaluation of these units' impact on culturable airborne bacteria.
TextSentencer_T124 20126-20308 Sentence denotes 32 This was confirmed in an investigation by Miller et al 4 that involved installation of upper-room UVGI units and evaluation of these units' impact on culturable airborne bacteria.
TextSentencer_T125 20309-20440 Sentence denotes More than 90% of the bacteria detected were inactivated; however, the rate was lower for more-resistant bacteria and fungal spores.
TextSentencer_T125 20309-20440 Sentence denotes More than 90% of the bacteria detected were inactivated; however, the rate was lower for more-resistant bacteria and fungal spores.
TextSentencer_T126 20441-20564 Sentence denotes That investigation also clearly demonstrated that room air must be mixed for UVGI to effectively inactivate microorganisms.
TextSentencer_T126 20441-20564 Sentence denotes That investigation also clearly demonstrated that room air must be mixed for UVGI to effectively inactivate microorganisms.
TextSentencer_T127 20565-20897 Sentence denotes When warm air entered the room via a duct close to the ceiling (which can occur in the winter when the heating system is turned on), the warm air simply ''rested'' on the much cooler air below, and the efficacy of the UVGI system was dramatically diminished because the microbes did not move up for exposure to the UV-C irradiation.
TextSentencer_T127 20565-20897 Sentence denotes When warm air entered the room via a duct close to the ceiling (which can occur in the winter when the heating system is turned on), the warm air simply ''rested'' on the much cooler air below, and the efficacy of the UVGI system was dramatically diminished because the microbes did not move up for exposure to the UV-C irradiation.
TextSentencer_T128 20898-20988 Sentence denotes No mixing fans were turned on during the experiment, but moderate ventilation was present.
TextSentencer_T128 20898-20988 Sentence denotes No mixing fans were turned on during the experiment, but moderate ventilation was present.
TextSentencer_T129 20989-21176 Sentence denotes The cleanliness of UV light bulbs and age of UV lamps should be checked periodically (approximately every 6 months) to ensure sufficient UV light intensity for germicidal activity (UV-C).
TextSentencer_T129 20989-21176 Sentence denotes The cleanliness of UV light bulbs and age of UV lamps should be checked periodically (approximately every 6 months) to ensure sufficient UV light intensity for germicidal activity (UV-C).
TextSentencer_T130 21177-21299 Sentence denotes The intensity of germicidal wavelength light decreases with age, and bulb ratings (hours of use) may vary by manufacturer.
TextSentencer_T130 21177-21299 Sentence denotes The intensity of germicidal wavelength light decreases with age, and bulb ratings (hours of use) may vary by manufacturer.
TextSentencer_T131 21300-21550 Sentence denotes 13 Upper-room UVGI is often seen as a cost-effective measure to supplement the general ventilation system in a room; however, the combination of the general ventilation system and UV lamps might not necessarily be implemented correctly within a room.
TextSentencer_T131 21300-21550 Sentence denotes 13 Upper-room UVGI is often seen as a cost-effective measure to supplement the general ventilation system in a room; however, the combination of the general ventilation system and UV lamps might not necessarily be implemented correctly within a room.
TextSentencer_T132 21551-21868 Sentence denotes For example, if the ventilation rate is too high, the particles may not be sufficiently exposed to the UV-C irradiation to ensure complete inactivation, or if the ventilation system does not provide good mixing within the room, airborne particles containing microbes might not even be exposed to the UV-C irradiation.
TextSentencer_T132 21551-21868 Sentence denotes For example, if the ventilation rate is too high, the particles may not be sufficiently exposed to the UV-C irradiation to ensure complete inactivation, or if the ventilation system does not provide good mixing within the room, airborne particles containing microbes might not even be exposed to the UV-C irradiation.
TextSentencer_T133 21869-22299 Sentence denotes 13 A well-designed upper-room UVGI system may effectively kill or inactivate most airborne droplet nuclei containing Mycobacterium spp if designed to provide an average UV fluence rate (ie, irradiance from all angles that is incident on a small region of space; a more accurate term than ''UV dose'') in the upper room in the range of 30-50 mW/cm 2 , provided that the other criteria stipulated in the CDC's TB guidelines are met.
TextSentencer_T133 21869-22299 Sentence denotes 13 A well-designed upper-room UVGI system may effectively kill or inactivate most airborne droplet nuclei containing Mycobacterium spp if designed to provide an average UV fluence rate (ie, irradiance from all angles that is incident on a small region of space; a more accurate term than ''UV dose'') in the upper room in the range of 30-50 mW/cm 2 , provided that the other criteria stipulated in the CDC's TB guidelines are met.
TextSentencer_T134 22300-22407 Sentence denotes 2 The fixtures should be installed to provide as uniform a UVGI distribution as possible in the upper room.
TextSentencer_T134 22300-22407 Sentence denotes 2 The fixtures should be installed to provide as uniform a UVGI distribution as possible in the upper room.
TextSentencer_T135 22408-22626 Sentence denotes 5 Schafer et al 33 developed a method to measure fluence rate and used it to verify that this rate varied as much as 3-fold in a typical room, depending on proximity to the lamp, and found that lamp failure was common.
TextSentencer_T135 22408-22626 Sentence denotes 5 Schafer et al 33 developed a method to measure fluence rate and used it to verify that this rate varied as much as 3-fold in a typical room, depending on proximity to the lamp, and found that lamp failure was common.
TextSentencer_T136 22627-22711 Sentence denotes This reinforces the need to monitor the efficacy of the lamps used in UVGI fixtures.
TextSentencer_T136 22627-22711 Sentence denotes This reinforces the need to monitor the efficacy of the lamps used in UVGI fixtures.
TextSentencer_T137 22712-22957 Sentence denotes Under experimental laboratory conditions with mechanical ventilation rates of up to 6 ACH, the rate at which microorganisms are killed or inactivated by UVGI systems appears to be additive with mechanical ventilation systems in well-mixed rooms.
TextSentencer_T137 22712-22957 Sentence denotes Under experimental laboratory conditions with mechanical ventilation rates of up to 6 ACH, the rate at which microorganisms are killed or inactivated by UVGI systems appears to be additive with mechanical ventilation systems in well-mixed rooms.
TextSentencer_T138 22958-23190 Sentence denotes 2 For other infectious agents, such as SARS-CoV and influenza, the mode of transmission is by droplets, which do not remain suspended in air for long periods of time, but fall out within a 2-m radius from a coughing/sneezing person.
TextSentencer_T138 22958-23190 Sentence denotes 2 For other infectious agents, such as SARS-CoV and influenza, the mode of transmission is by droplets, which do not remain suspended in air for long periods of time, but fall out within a 2-m radius from a coughing/sneezing person.
TextSentencer_T139 23191-23331 Sentence denotes Even the most robust HVAC system is unlikely to achieve sufficient air mixing to provide efficient kill of microbes transmitted by droplets.
TextSentencer_T139 23191-23331 Sentence denotes Even the most robust HVAC system is unlikely to achieve sufficient air mixing to provide efficient kill of microbes transmitted by droplets.
TextSentencer_T140 23332-23436 Sentence denotes These particles never reach the upper-room UV zone; thus, an alternate method of disinfection is needed.
TextSentencer_T140 23332-23436 Sentence denotes These particles never reach the upper-room UV zone; thus, an alternate method of disinfection is needed.
TextSentencer_T141 23437-23774 Sentence denotes 34 Escombe et al 35 recently investigated impact of upward-facing UV light fixtures installed in ceilings of a negative-pressure TB isolation ward and ceilingmounted air ionization fixtures in an animal enclosure chamber, using a guinea pig air sampling model that involved exposure of the animals to exhaust air from the isolation ward.
TextSentencer_T141 23437-23774 Sentence denotes 34 Escombe et al 35 recently investigated impact of upward-facing UV light fixtures installed in ceilings of a negative-pressure TB isolation ward and ceilingmounted air ionization fixtures in an animal enclosure chamber, using a guinea pig air sampling model that involved exposure of the animals to exhaust air from the isolation ward.
TextSentencer_T142 23775-23981 Sentence denotes With this animal model, 35% of controls exposed to untreated exhaust air from the TB ward developed TB infection, whereas frequency was reduced to 14% and 9.5% with use of an ionizer and UVGI, respectively.
TextSentencer_T142 23775-23981 Sentence denotes With this animal model, 35% of controls exposed to untreated exhaust air from the TB ward developed TB infection, whereas frequency was reduced to 14% and 9.5% with use of an ionizer and UVGI, respectively.
TextSentencer_T143 23982-24185 Sentence denotes They concluded that ''provided there is adequate mixing of room air, an upper-room UVGI fixture is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings.'' 35
TextSentencer_T143 23982-24185 Sentence denotes They concluded that ''provided there is adequate mixing of room air, an upper-room UVGI fixture is an effective, low-cost intervention for use in TB infection control in high-risk clinical settings.'' 35
TextSentencer_T144 24186-24277 Sentence denotes Critical factors that affect the efficacy of UVGI include temperature, RH, and lamp output.
TextSentencer_T144 24186-24277 Sentence denotes Critical factors that affect the efficacy of UVGI include temperature, RH, and lamp output.
TextSentencer_T145 24278-24395 Sentence denotes A number of studies have indicated that the effectiveness of upper-room UVGI systems decreases as humidity increases.
TextSentencer_T145 24278-24395 Sentence denotes A number of studies have indicated that the effectiveness of upper-room UVGI systems decreases as humidity increases.
TextSentencer_T146 24396-24502 Sentence denotes For optimal efficiency, RH should be controlled to 60% or less when upper-room UVGI systems are installed.
TextSentencer_T146 24396-24502 Sentence denotes For optimal efficiency, RH should be controlled to 60% or less when upper-room UVGI systems are installed.
TextSentencer_T147 24503-24567 Sentence denotes Temperature should be kept between 688F and 75 8F (20 8C-24 8C).
TextSentencer_T147 24503-24567 Sentence denotes Temperature should be kept between 688F and 75 8F (20 8C-24 8C).
TextSentencer_T148 24568-24829 Sentence denotes Both of these suggestions are consistent with 2010 Facility Guidelines Institute (FGI) and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recommendations in ASHRAE Standard 170 (now part of the FGI Guidelines Standards).
TextSentencer_T148 24568-24829 Sentence denotes Both of these suggestions are consistent with 2010 Facility Guidelines Institute (FGI) and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recommendations in ASHRAE Standard 170 (now part of the FGI Guidelines Standards).
TextSentencer_T149 24830-24944 Sentence denotes 36 The ASHRAE Handbook also provides comprehensive recommendations for installation and operation of UVGI systems.
TextSentencer_T149 24830-24944 Sentence denotes 36 The ASHRAE Handbook also provides comprehensive recommendations for installation and operation of UVGI systems.
TextSentencer_T150 24945-25194 Sentence denotes 37 Experimental upper-room UVGI systems used in rooms with aerosolized bacteria (including surrogates of M tuberculosis) have shown that the higher the UV fluence rate produced in the upper air of a room, the greater the effectiveness of the system.
TextSentencer_T150 24945-25194 Sentence denotes 37 Experimental upper-room UVGI systems used in rooms with aerosolized bacteria (including surrogates of M tuberculosis) have shown that the higher the UV fluence rate produced in the upper air of a room, the greater the effectiveness of the system.
TextSentencer_T151 25195-25426 Sentence denotes 4, 38, 39 Based on the results of experiments with upper-room UVGI systems and aerosolized bacteria in bench-scale reactors, it is apparent that the greater the UV fluence rate in the irradiated zone, the more effective the system.
TextSentencer_T151 25195-25426 Sentence denotes 4, 38, 39 Based on the results of experiments with upper-room UVGI systems and aerosolized bacteria in bench-scale reactors, it is apparent that the greater the UV fluence rate in the irradiated zone, the more effective the system.
TextSentencer_T152 25427-25619 Sentence denotes 40, 41 However, there appears to be an upper threshold after which an increase in UVGI does not directly correspond to an increase in the system's ability to kill or inactivate microorganisms.
TextSentencer_T152 25427-25619 Sentence denotes 40, 41 However, there appears to be an upper threshold after which an increase in UVGI does not directly correspond to an increase in the system's ability to kill or inactivate microorganisms.
TextSentencer_T153 25620-25763 Sentence denotes 4, 13, 42, 43 Miller et al 4 reported decreased effectiveness of the UVGI system when the UV fixtures were placed on only one side of the room.
TextSentencer_T153 25620-25763 Sentence denotes 4, 13, 42, 43 Miller et al 4 reported decreased effectiveness of the UVGI system when the UV fixtures were placed on only one side of the room.
TextSentencer_T154 25764-25982 Sentence denotes This is consistent with the findings of Riley and Permutt, 44 who reported that a wider distribution of low-irradiance UV lamps was more efficient compared with the use of one centrally located high-irradiance UV lamp.
TextSentencer_T154 25764-25982 Sentence denotes This is consistent with the findings of Riley and Permutt, 44 who reported that a wider distribution of low-irradiance UV lamps was more efficient compared with the use of one centrally located high-irradiance UV lamp.
TextSentencer_T155 25983-26117 Sentence denotes This suggests that upperroom UVGI systems should be installed to provide the most uniform UVGI distribution in the upper air possible.
TextSentencer_T155 25983-26117 Sentence denotes This suggests that upperroom UVGI systems should be installed to provide the most uniform UVGI distribution in the upper air possible.
TextSentencer_T156 26118-26271 Sentence denotes In most of the studies that form the basis of the irradiance guidelines, the bacteria studied were primarily single cells aerosolized in deionized water.
TextSentencer_T156 26118-26271 Sentence denotes In most of the studies that form the basis of the irradiance guidelines, the bacteria studied were primarily single cells aerosolized in deionized water.
TextSentencer_T157 26272-26422 Sentence denotes This lack of a mucus coating could possibly make these bacteria more sensitive to UVGI compared with bacteria in droplet nuclei from an infected host.
TextSentencer_T157 26272-26422 Sentence denotes This lack of a mucus coating could possibly make these bacteria more sensitive to UVGI compared with bacteria in droplet nuclei from an infected host.
TextSentencer_T158 26423-26587 Sentence denotes 45 The killing or deactivation of 63% of droplet nuclei in a room by UVGI is equivalent to 1 ACH in terms of reduced total droplet nuclei concentration in the room.
TextSentencer_T158 26423-26587 Sentence denotes 45 The killing or deactivation of 63% of droplet nuclei in a room by UVGI is equivalent to 1 ACH in terms of reduced total droplet nuclei concentration in the room.
TextSentencer_T159 26588-26684 Sentence denotes 3 This reduction of droplet nuclei by a method other than mechanical ventilation is termed eACH.
TextSentencer_T159 26588-26684 Sentence denotes 3 This reduction of droplet nuclei by a method other than mechanical ventilation is termed eACH.
TextSentencer_T160 26685-26753 Sentence denotes UVGI lamps can be installed in a various locations in a HVAC system.
TextSentencer_T160 26685-26753 Sentence denotes UVGI lamps can be installed in a various locations in a HVAC system.
TextSentencer_T161 26754-26848 Sentence denotes One possible location is inside the AHU, typically in front of the cooling coils and drip pan.
TextSentencer_T161 26754-26848 Sentence denotes One possible location is inside the AHU, typically in front of the cooling coils and drip pan.
TextSentencer_T162 26849-27035 Sentence denotes There are anecdotal reports that this configuration results in energy conservation and maintenance cost savings, but more rigorous study is needed to reproduce and validate these claims.
TextSentencer_T162 26849-27035 Sentence denotes There are anecdotal reports that this configuration results in energy conservation and maintenance cost savings, but more rigorous study is needed to reproduce and validate these claims.
TextSentencer_T163 27036-27188 Sentence denotes Some manufacturers of these systems have also made claims of reduced incidence of health care-associated infections (HAIs) with the use of UVGI in AHUs.
TextSentencer_T163 27036-27188 Sentence denotes Some manufacturers of these systems have also made claims of reduced incidence of health care-associated infections (HAIs) with the use of UVGI in AHUs.
TextSentencer_T164 27189-27295 Sentence denotes To date, however, there is little, if any, supportive evidence in the peer-reviewed scientific literature.
TextSentencer_T164 27189-27295 Sentence denotes To date, however, there is little, if any, supportive evidence in the peer-reviewed scientific literature.
TextSentencer_T165 27296-27447 Sentence denotes Many of the published investigations rely on environmental surface or air sampling cultures or laboratory-based animal studies for inferential support.
TextSentencer_T165 27296-27447 Sentence denotes Many of the published investigations rely on environmental surface or air sampling cultures or laboratory-based animal studies for inferential support.
TextSentencer_T166 27448-27591 Sentence denotes Our assessment of the available literature indicates claims of reduced HAIs from AHU-installed UVGI in health care facilities remain unfounded.
TextSentencer_T166 27448-27591 Sentence denotes Our assessment of the available literature indicates claims of reduced HAIs from AHU-installed UVGI in health care facilities remain unfounded.
TextSentencer_T167 27592-27722 Sentence denotes There is some evidence of fewer complaints related to indoor air quality in buildings with systems containing UVGI inside the AHU.
TextSentencer_T167 27592-27722 Sentence denotes There is some evidence of fewer complaints related to indoor air quality in buildings with systems containing UVGI inside the AHU.
TextSentencer_T168 27723-27963 Sentence denotes 46 Levetin et al 47 provided some evidence for this by demonstrating a significantly lower concentration of fungal spores on a floor of a building with an in-duct UVGI system compared with a floor in the same building without such a system.
TextSentencer_T168 27723-27963 Sentence denotes 46 Levetin et al 47 provided some evidence for this by demonstrating a significantly lower concentration of fungal spores on a floor of a building with an in-duct UVGI system compared with a floor in the same building without such a system.
TextSentencer_T169 27964-28077 Sentence denotes The spores recovered in the building were the same as from insulation material in the ventilation ducts, however.
TextSentencer_T169 27964-28077 Sentence denotes The spores recovered in the building were the same as from insulation material in the ventilation ducts, however.
TextSentencer_T170 28078-28243 Sentence denotes The authors concluded that few spores from the outdoors passed through filters in the AHUs, but that the spores developed when the HVAC system was turned on and off.
TextSentencer_T170 28078-28243 Sentence denotes The authors concluded that few spores from the outdoors passed through filters in the AHUs, but that the spores developed when the HVAC system was turned on and off.
TextSentencer_T171 28244-28370 Sentence denotes Notably, they noted that ''as a result, we cannot say that the UV-C radiation had a direct effect on spores in the air stream.
TextSentencer_T171 28244-28370 Sentence denotes Notably, they noted that ''as a result, we cannot say that the UV-C radiation had a direct effect on spores in the air stream.
TextSentencer_T172 28371-28693 Sentence denotes The effectiveness of UV-C lamps seemed to be localized, because visual inspection indicated there was conspicuous fungal growth in the downstream duct insulation lining.'' 47 UV lamps also can be placed inside supply or return air ducts to disinfect the air before it is supplied to an occupied space or when recirculated.
TextSentencer_T172 28371-28693 Sentence denotes The effectiveness of UV-C lamps seemed to be localized, because visual inspection indicated there was conspicuous fungal growth in the downstream duct insulation lining.'' 47 UV lamps also can be placed inside supply or return air ducts to disinfect the air before it is supplied to an occupied space or when recirculated.
TextSentencer_T173 28694-28738 Sentence denotes UV irradiation by itself does not clean air.
TextSentencer_T173 28694-28738 Sentence denotes UV irradiation by itself does not clean air.
TextSentencer_T174 28739-28895 Sentence denotes The microorganisms are still there, and in the case of some microorganisms, might still contain the ability to cause noninfectious (eg, allergenic) disease.
TextSentencer_T174 28739-28895 Sentence denotes The microorganisms are still there, and in the case of some microorganisms, might still contain the ability to cause noninfectious (eg, allergenic) disease.
TextSentencer_T175 28896-29036 Sentence denotes Although UV potentially can destroy allergenic sites on the surface of a bioaerosol, this ability has yet not been documented or quantified.
TextSentencer_T175 28896-29036 Sentence denotes Although UV potentially can destroy allergenic sites on the surface of a bioaerosol, this ability has yet not been documented or quantified.
TextSentencer_T176 29037-29226 Sentence denotes 47 Bacterial inactivation studies using Bacillus Calmette-Guérin (BCG; a strain of Mycobacterium bovis) and Serratia marcescens have estimated the effect of UVGI as equivalent to 10-39 ACH.
TextSentencer_T176 29037-29226 Sentence denotes 47 Bacterial inactivation studies using Bacillus Calmette-Guérin (BCG; a strain of Mycobacterium bovis) and Serratia marcescens have estimated the effect of UVGI as equivalent to 10-39 ACH.
TextSentencer_T177 29227-29396 Sentence denotes 34 However, another study suggested that UVGI may result in fewer equivalent ACH in the patient-care zone, especially if the mixing of air between zones is insufficient.
TextSentencer_T177 29227-29396 Sentence denotes 34 However, another study suggested that UVGI may result in fewer equivalent ACH in the patient-care zone, especially if the mixing of air between zones is insufficient.
TextSentencer_T178 29397-29614 Sentence denotes 48 The use of fans or HVAC systems to generate air movement and good mixing might increase the effectiveness of UVGI by ensuring exposure of airborne microorganisms to the light energy for a sufficient length of time.
TextSentencer_T178 29397-29614 Sentence denotes 48 The use of fans or HVAC systems to generate air movement and good mixing might increase the effectiveness of UVGI by ensuring exposure of airborne microorganisms to the light energy for a sufficient length of time.
TextSentencer_T179 29615-29617 Sentence denotes 35
TextSentencer_T179 29615-29617 Sentence denotes 35
TextSentencer_T180 29619-29718 Sentence denotes UVGI has been used for disinfection of water, but that application is not addressed in this review.
TextSentencer_T180 29619-29718 Sentence denotes UVGI has been used for disinfection of water, but that application is not addressed in this review.
TextSentencer_T181 29719-29763 Sentence denotes It has also been used to disinfect surfaces.
TextSentencer_T181 29719-29763 Sentence denotes It has also been used to disinfect surfaces.
TextSentencer_T182 29764-30027 Sentence denotes One study found that the effectiveness of this application is limited by the low penetrating power of UVGI, and thus it is currently limited to decontaminating surfaces when conventional methods, such as the use of liquid chemical disinfectants, are not feasible.
TextSentencer_T182 29764-30027 Sentence denotes One study found that the effectiveness of this application is limited by the low penetrating power of UVGI, and thus it is currently limited to decontaminating surfaces when conventional methods, such as the use of liquid chemical disinfectants, are not feasible.
TextSentencer_T183 30028-30135 Sentence denotes 31 Some studies also have explored disinfection of medical devices and other high-frequency touch surfaces.
TextSentencer_T183 30028-30135 Sentence denotes 31 Some studies also have explored disinfection of medical devices and other high-frequency touch surfaces.
TextSentencer_T184 30136-30408 Sentence denotes Sweeney and Dancer 49 found that UVGI disinfection of computer keyboards without mechanical friction from cleaning had no impact on bioburden for 72% of the 68 keyboards in their study, and concluded that physical cleaning is of greatest importance before the use of UVGI.
TextSentencer_T184 30136-30408 Sentence denotes Sweeney and Dancer 49 found that UVGI disinfection of computer keyboards without mechanical friction from cleaning had no impact on bioburden for 72% of the 68 keyboards in their study, and concluded that physical cleaning is of greatest importance before the use of UVGI.
TextSentencer_T185 30409-30604 Sentence denotes Kac et al 50 found that UVGI effectively disinfected endocavitary ultrasound probes, but only if used in combination with a surface disinfectant applied with a cloth and with mechanical friction.
TextSentencer_T185 30409-30604 Sentence denotes Kac et al 50 found that UVGI effectively disinfected endocavitary ultrasound probes, but only if used in combination with a surface disinfectant applied with a cloth and with mechanical friction.
TextSentencer_T186 30605-30839 Sentence denotes Interestingly, both of these investigations highlight the adjunctive impact of UVGI following traditional cleaning and disinfection for medical devices and other surfaces, whivch is consistent with use of UVGI for disinfection of air.
TextSentencer_T186 30605-30839 Sentence denotes Interestingly, both of these investigations highlight the adjunctive impact of UVGI following traditional cleaning and disinfection for medical devices and other surfaces, whivch is consistent with use of UVGI for disinfection of air.
TextSentencer_T187 30840-31116 Sentence denotes More recently Rutala et al 51 presented unpublished results of their study of ''no-touch'' full room disinfection with an automated, portable UV-C device that uses mirrors to ''bounce'' UVGI around a room to reach all surfaces, including those not directly exposed to fluence.
TextSentencer_T187 30840-31116 Sentence denotes More recently Rutala et al 51 presented unpublished results of their study of ''no-touch'' full room disinfection with an automated, portable UV-C device that uses mirrors to ''bounce'' UVGI around a room to reach all surfaces, including those not directly exposed to fluence.
TextSentencer_T188 31117-31306 Sentence denotes They reported substantial log reductions in vegetative bacteria (3) (4) within 15 minutes of exposure and in spore-forming bacteria, such as C difficile (2-3), after 50 minutes of exposure.
TextSentencer_T188 31117-31306 Sentence denotes They reported substantial log reductions in vegetative bacteria (3) (4) within 15 minutes of exposure and in spore-forming bacteria, such as C difficile (2-3), after 50 minutes of exposure.
TextSentencer_T189 31307-31440 Sentence denotes An analytical model for evaluating the UV dose in steady-state conditions using the Eulerian system was proposed by Memarzadeh et al.
TextSentencer_T189 31307-31440 Sentence denotes An analytical model for evaluating the UV dose in steady-state conditions using the Eulerian system was proposed by Memarzadeh et al.
TextSentencer_T190 31441-31581 Sentence denotes 48 Computational fluid dynamics (CFD) was used to study the efficacy of inactivation of airborne bacteria by upper-room UVGI in a test room.
TextSentencer_T190 31441-31581 Sentence denotes 48 Computational fluid dynamics (CFD) was used to study the efficacy of inactivation of airborne bacteria by upper-room UVGI in a test room.
TextSentencer_T191 31582-31636 Sentence denotes Several UV lamp configurations were used in the model.
TextSentencer_T191 31582-31636 Sentence denotes Several UV lamp configurations were used in the model.
TextSentencer_T192 31637-31764 Sentence denotes Compared with available experimental data, the proposed model closely predicts the percentage of particles inactivated by UVGI.
TextSentencer_T192 31637-31764 Sentence denotes Compared with available experimental data, the proposed model closely predicts the percentage of particles inactivated by UVGI.
TextSentencer_T193 31765-31923 Sentence denotes The proposed model was used to study the effects of ventilation flow rate and UV fixture configuration on inactivation of airborne bacteria in a test chamber.
TextSentencer_T193 31765-31923 Sentence denotes The proposed model was used to study the effects of ventilation flow rate and UV fixture configuration on inactivation of airborne bacteria in a test chamber.
TextSentencer_T194 31924-32017 Sentence denotes The Lagrangian system model was also applied in the same test chamber for a similar scenario.
TextSentencer_T194 31924-32017 Sentence denotes The Lagrangian system model was also applied in the same test chamber for a similar scenario.
TextSentencer_T195 32018-32137 Sentence denotes This CFD model demonstrates that the percentage of UVGI inactivation is higher when the ventilation flow rate is lower.
TextSentencer_T195 32018-32137 Sentence denotes This CFD model demonstrates that the percentage of UVGI inactivation is higher when the ventilation flow rate is lower.
TextSentencer_T196 32138-32273 Sentence denotes Increasing the ventilation flow rate from 2 to 6 ACH reduces the residence time of a pass through the UV zone from 24.7 to 8.3 seconds.
TextSentencer_T196 32138-32273 Sentence denotes Increasing the ventilation flow rate from 2 to 6 ACH reduces the residence time of a pass through the UV zone from 24.7 to 8.3 seconds.
TextSentencer_T197 32274-32368 Sentence denotes In the latter case, the dosage is then only˜35% of the total dose received in the former case.
TextSentencer_T197 32274-32368 Sentence denotes In the latter case, the dosage is then only˜35% of the total dose received in the former case.
TextSentencer_T198 32369-32589 Sentence denotes For upper-room UVGI to be effective, the aerosolized infectious particles must be moved from the lower part of the room, where they are produced by a person coughing or sneezing, to the germicidal zone in the upper room.
TextSentencer_T198 32369-32589 Sentence denotes For upper-room UVGI to be effective, the aerosolized infectious particles must be moved from the lower part of the room, where they are produced by a person coughing or sneezing, to the germicidal zone in the upper room.
TextSentencer_T199 32590-32755 Sentence denotes Practical considerations prohibit the ideal situation of UVGI cleansing of all infectious particles in a single pass when they move through the upper-room UVGI zone.
TextSentencer_T199 32590-32755 Sentence denotes Practical considerations prohibit the ideal situation of UVGI cleansing of all infectious particles in a single pass when they move through the upper-room UVGI zone.
TextSentencer_T200 32756-32838 Sentence denotes Another consideration is how rapidly microorganisms proceed through the UVGI zone.
TextSentencer_T200 32756-32838 Sentence denotes Another consideration is how rapidly microorganisms proceed through the UVGI zone.
TextSentencer_T201 32839-32995 Sentence denotes A higher frequency of ACH limits the exposure time of the infectious particles to the UVGI and thus is likely to have less effective antimicrobial activity.
TextSentencer_T201 32839-32995 Sentence denotes A higher frequency of ACH limits the exposure time of the infectious particles to the UVGI and thus is likely to have less effective antimicrobial activity.
TextSentencer_T202 32996-33128 Sentence denotes In practice, the effectiveness of a UVGI installation is determined by the following factors: d Fixture used to house the UV-C lamp.
TextSentencer_T202 32996-33128 Sentence denotes In practice, the effectiveness of a UVGI installation is determined by the following factors: d Fixture used to house the UV-C lamp.
TextSentencer_T203 33129-33301 Sentence denotes This determines how much of the radiation discharged from the UV lamp is actually emitted from the fixture and how it is distributed. d Environmental sustainability issues.
TextSentencer_T203 33129-33301 Sentence denotes This determines how much of the radiation discharged from the UV lamp is actually emitted from the fixture and how it is distributed. d Environmental sustainability issues.
TextSentencer_T204 33302-33452 Sentence denotes Most UV-C lamps use low-pressure mercury, have a limited life span, and require environmental precautions for disposal. d Distance from the UV-C lamp.
TextSentencer_T204 33302-33452 Sentence denotes Most UV-C lamps use low-pressure mercury, have a limited life span, and require environmental precautions for disposal. d Distance from the UV-C lamp.
TextSentencer_T205 33453-33601 Sentence denotes The distance of airborne infectious agents from the fixture will determine the irradiance level and thus the germicidal efficacy. d Airflow pattern.
TextSentencer_T205 33453-33601 Sentence denotes The distance of airborne infectious agents from the fixture will determine the irradiance level and thus the germicidal efficacy. d Airflow pattern.
TextSentencer_T206 33602-33693 Sentence denotes This affects how long the bacteria and viruses are exposed to the UV radiation. d Humidity.
TextSentencer_T206 33602-33693 Sentence denotes This affects how long the bacteria and viruses are exposed to the UV radiation. d Humidity.
TextSentencer_T207 33694-33819 Sentence denotes The humidity of the atmosphere is key, because water makes the infectious agent less susceptible to damage from UV radiation.
TextSentencer_T207 33694-33819 Sentence denotes The humidity of the atmosphere is key, because water makes the infectious agent less susceptible to damage from UV radiation.
TextSentencer_T208 33820-33887 Sentence denotes The higher the RH, the less likely an aqueous aerosol will dry out.
TextSentencer_T208 33820-33887 Sentence denotes The higher the RH, the less likely an aqueous aerosol will dry out.
TextSentencer_T209 33888-33941 Sentence denotes For maximum effectiveness of UVGI, RH should be ,75%.
TextSentencer_T209 33888-33941 Sentence denotes For maximum effectiveness of UVGI, RH should be ,75%.
TextSentencer_T210 33942-33944 Sentence denotes 34
TextSentencer_T210 33942-33944 Sentence denotes 34
TextSentencer_T211 33945-34143 Sentence denotes According to an American Biological Safety Association position paper, biological effects in humans from overexposure to UV-C radiation vary with wavelength, photon energy, and duration of exposure.
TextSentencer_T211 33945-34143 Sentence denotes According to an American Biological Safety Association position paper, biological effects in humans from overexposure to UV-C radiation vary with wavelength, photon energy, and duration of exposure.
TextSentencer_T212 34144-34208 Sentence denotes 52 In general, adverse effects are limited to the skin and eyes.
TextSentencer_T212 34144-34208 Sentence denotes 52 In general, adverse effects are limited to the skin and eyes.
TextSentencer_T213 34209-34303 Sentence denotes Erythema (eg, reddening of the skin, as in sunburn) is the most commonly observed skin effect.
TextSentencer_T213 34209-34303 Sentence denotes Erythema (eg, reddening of the skin, as in sunburn) is the most commonly observed skin effect.
TextSentencer_T214 34304-34412 Sentence denotes Chronic exposure to UV radiation can accelerate the skin aging process and increase the risk of skin cancer.
TextSentencer_T214 34304-34412 Sentence denotes Chronic exposure to UV radiation can accelerate the skin aging process and increase the risk of skin cancer.
TextSentencer_T215 34413-34498 Sentence denotes The National Toxicology Program (NTP) classifies UV-C as a probable human carcinogen.
TextSentencer_T215 34413-34498 Sentence denotes The National Toxicology Program (NTP) classifies UV-C as a probable human carcinogen.
TextSentencer_T216 34499-34612 Sentence denotes Excessive exposure to UV-C radiation can adversely affect the eyes, causing photokeratitis and/or conjunctivitis.
TextSentencer_T216 34499-34612 Sentence denotes Excessive exposure to UV-C radiation can adversely affect the eyes, causing photokeratitis and/or conjunctivitis.
TextSentencer_T217 34613-34868 Sentence denotes Based on the current guidelines, repeated exposure at or below the current guideline would not be expected to cause adverse health effects; however, it should be emphasized that UV radiation has been implicated in both skin cancer and cataracts in humans.
TextSentencer_T217 34613-34868 Sentence denotes Based on the current guidelines, repeated exposure at or below the current guideline would not be expected to cause adverse health effects; however, it should be emphasized that UV radiation has been implicated in both skin cancer and cataracts in humans.
TextSentencer_T218 34869-35017 Sentence denotes On May 18, 2007, NIOSH received a request from the Director of Environmental Affairs at Brigham and Women's Hospital (BWH) in Boston, Massachusetts.
TextSentencer_T218 34869-35017 Sentence denotes On May 18, 2007, NIOSH received a request from the Director of Environmental Affairs at Brigham and Women's Hospital (BWH) in Boston, Massachusetts.
TextSentencer_T219 35018-35243 Sentence denotes Some BWH orthopedic surgical staff members were concerned about unspecified skin and eye symptoms, which they attributed to germicidal UV-C radiation produced by ceiling-mounted UVGI lamps in orthopedic operating rooms (ORs).
TextSentencer_T219 35018-35243 Sentence denotes Some BWH orthopedic surgical staff members were concerned about unspecified skin and eye symptoms, which they attributed to germicidal UV-C radiation produced by ceiling-mounted UVGI lamps in orthopedic operating rooms (ORs).
TextSentencer_T220 35244-35547 Sentence denotes The use of UVGI in orthopedic ORs was investigated by the Occupational Safety and Health Administration (OSHA) on January 19, 2007 , in response to a formal complaint submitted after staff discovered that the UVGI lamp controls in an OR had been tampered with and set at an inappropriately high setting.
TextSentencer_T220 35244-35547 Sentence denotes The use of UVGI in orthopedic ORs was investigated by the Occupational Safety and Health Administration (OSHA) on January 19, 2007 , in response to a formal complaint submitted after staff discovered that the UVGI lamp controls in an OR had been tampered with and set at an inappropriately high setting.
TextSentencer_T221 35548-35781 Sentence denotes After an inspection, OSHA recommended that BWH provide annual UV-C and personal protective equipment (PPE) training and medical screening for all affected employees, as well as ensure that all affected employees use the required PPE.
TextSentencer_T221 35548-35781 Sentence denotes After an inspection, OSHA recommended that BWH provide annual UV-C and personal protective equipment (PPE) training and medical screening for all affected employees, as well as ensure that all affected employees use the required PPE.
TextSentencer_T222 35782-35948 Sentence denotes In July 2008, BWH moved the orthopedic operating suite to an area equipped with laminar airflow and discontinued the use of UVGI for intraoperative infection control.
TextSentencer_T222 35782-35948 Sentence denotes In July 2008, BWH moved the orthopedic operating suite to an area equipped with laminar airflow and discontinued the use of UVGI for intraoperative infection control.
TextSentencer_T223 35949-36060 Sentence denotes NIOSH investigators recommended the use of alternative infection control technologies, such as laminar airflow.
TextSentencer_T223 35949-36060 Sentence denotes NIOSH investigators recommended the use of alternative infection control technologies, such as laminar airflow.
TextSentencer_T224 36061-36063 Sentence denotes 53
TextSentencer_T224 36061-36063 Sentence denotes 53
TextSentencer_T225 36065-36441 Sentence denotes The use of direct UVGI as an air-cleaning method for intraoperative infection control is a relatively uncommon application that has been used by some surgeons since the 1930s. [54] [55] [56] Some evidence suggests that the use of UVGI in this manner might reduce the incidence of surgical site infections by minimizing intraoperative levels of airborne bacterial contaminants.
TextSentencer_T225 36065-36441 Sentence denotes The use of direct UVGI as an air-cleaning method for intraoperative infection control is a relatively uncommon application that has been used by some surgeons since the 1930s. [54] [55] [56] Some evidence suggests that the use of UVGI in this manner might reduce the incidence of surgical site infections by minimizing intraoperative levels of airborne bacterial contaminants.
TextSentencer_T226 36442-36556 Sentence denotes This design differs from upper-room devices in that the UV-C irradiation is directed down to expose the entire OR.
TextSentencer_T226 36442-36556 Sentence denotes This design differs from upper-room devices in that the UV-C irradiation is directed down to expose the entire OR.
TextSentencer_T227 36557-36622 Sentence denotes Eye protection and other attire are required for those in the OR.
TextSentencer_T227 36557-36622 Sentence denotes Eye protection and other attire are required for those in the OR.
TextSentencer_T228 36623-36914 Sentence denotes The relative efficacy of direct UVGI on intraoperative air quality and prevention of infection has not been well defined, however, because studies that have examined its use did so at a variety of UV intensities in association with other infection prevention methods and surgical techniques.
TextSentencer_T228 36623-36914 Sentence denotes The relative efficacy of direct UVGI on intraoperative air quality and prevention of infection has not been well defined, however, because studies that have examined its use did so at a variety of UV intensities in association with other infection prevention methods and surgical techniques.
TextSentencer_T229 36915-37055 Sentence denotes In addition, most studies have been observational, before-after investigations, which are limited by biases and other confounding variables.
TextSentencer_T229 36915-37055 Sentence denotes In addition, most studies have been observational, before-after investigations, which are limited by biases and other confounding variables.
TextSentencer_T230 37056-37256 Sentence denotes Investigators have reported that UVGI is usually used not alone, but rather in conjunction with laminar airflow or body exhaust techniques, with discrepancies in wound rates under the same conditions.
TextSentencer_T230 37056-37256 Sentence denotes Investigators have reported that UVGI is usually used not alone, but rather in conjunction with laminar airflow or body exhaust techniques, with discrepancies in wound rates under the same conditions.
TextSentencer_T231 37257-37334 Sentence denotes 56 The CDC recommends against using UVGI to prevent surgical site infections.
TextSentencer_T231 37257-37334 Sentence denotes 56 The CDC recommends against using UVGI to prevent surgical site infections.
TextSentencer_T232 37335-37471 Sentence denotes 26 Overall, for general ventilation effectiveness, there is little advantage to increasing the effectiveness of the UVGI beyond 4-6 ACH.
TextSentencer_T232 37335-37471 Sentence denotes 26 Overall, for general ventilation effectiveness, there is little advantage to increasing the effectiveness of the UVGI beyond 4-6 ACH.
TextSentencer_T233 37472-37631 Sentence denotes UVGI is effective when at low ACH, and its efficacy diminishes as ACH increases, because the kill rate is dependent on the duration of exposure to the UV dose.
TextSentencer_T233 37472-37631 Sentence denotes UVGI is effective when at low ACH, and its efficacy diminishes as ACH increases, because the kill rate is dependent on the duration of exposure to the UV dose.
TextSentencer_T234 37632-37688 Sentence denotes With high ACH, exposure time is significantly decreased.
TextSentencer_T234 37632-37688 Sentence denotes With high ACH, exposure time is significantly decreased.
TextSentencer_T235 37689-37807 Sentence denotes For personnel safety, NIOSH strongly encourages employers to protect employees using a hierarchy of controls approach.
TextSentencer_T235 37689-37807 Sentence denotes For personnel safety, NIOSH strongly encourages employers to protect employees using a hierarchy of controls approach.
TextSentencer_T236 37808-37932 Sentence denotes The objective of this approach is to minimize the risk of failure of preventive measures, resulting in a hazardous exposure.
TextSentencer_T236 37808-37932 Sentence denotes The objective of this approach is to minimize the risk of failure of preventive measures, resulting in a hazardous exposure.
TextSentencer_T237 37933-38047 Sentence denotes According to the hierarchy, initial efforts should be made to eliminate the hazardous agent or source of exposure.
TextSentencer_T237 37933-38047 Sentence denotes According to the hierarchy, initial efforts should be made to eliminate the hazardous agent or source of exposure.
TextSentencer_T238 38048-38260 Sentence denotes With regard to intraoperative UVGI use, this could be achieved by substituting other infection prevention methods or technologies, such as vertical laminar air flow, before implementing direct UVGI inside the OR.
TextSentencer_T238 38048-38260 Sentence denotes With regard to intraoperative UVGI use, this could be achieved by substituting other infection prevention methods or technologies, such as vertical laminar air flow, before implementing direct UVGI inside the OR.
TextSentencer_T239 38261-38516 Sentence denotes 53 It should be noted that a more recent design for the OR uses nonaspirating diffusers with unidirectional airflow over the surgical site but at lower velocities than traditional high-velocity laminar sir flow, thereby minimizing the risk of hypothermia.
TextSentencer_T239 38261-38516 Sentence denotes 53 It should be noted that a more recent design for the OR uses nonaspirating diffusers with unidirectional airflow over the surgical site but at lower velocities than traditional high-velocity laminar sir flow, thereby minimizing the risk of hypothermia.
TextSentencer_T240 38517-38612 Sentence denotes This design is now required in the 2010 FGI guidelines 36 and is described in detail elsewhere.
TextSentencer_T240 38517-38612 Sentence denotes This design is now required in the 2010 FGI guidelines 36 and is described in detail elsewhere.
TextSentencer_T241 38613-38615 Sentence denotes 57
TextSentencer_T241 38613-38615 Sentence denotes 57
TextSentencer_T242 38617-39054 Sentence denotes Given the foregoing discussion, we recommend that UVGI system designers take the following considerations into account: d Apply safety factors to their designs, particularly as they depart from operating modes for which they have performance data and field experience. d Know the actual lamp output under the most challenging operating conditions. d Avoid relying solely on design equations to determine the performance of their systems.
TextSentencer_T242 38617-39054 Sentence denotes Given the foregoing discussion, we recommend that UVGI system designers take the following considerations into account: d Apply safety factors to their designs, particularly as they depart from operating modes for which they have performance data and field experience. d Know the actual lamp output under the most challenging operating conditions. d Avoid relying solely on design equations to determine the performance of their systems.
TextSentencer_T243 39055-39231 Sentence denotes Actual testing with the contaminants of interest is highly recommended. d View claims regarding UVGI systems' high level of inactivation of pathogenic bioaerosols with caution.
TextSentencer_T243 39055-39231 Sentence denotes Actual testing with the contaminants of interest is highly recommended. d View claims regarding UVGI systems' high level of inactivation of pathogenic bioaerosols with caution.
TextSentencer_T244 39232-39419 Sentence denotes Whereas the microbiological science underlying these conclusions applies to pathogenic bioaerosols as well as environmental organisms, much greater caution is required in the former case.
TextSentencer_T244 39232-39419 Sentence denotes Whereas the microbiological science underlying these conclusions applies to pathogenic bioaerosols as well as environmental organisms, much greater caution is required in the former case.
TextSentencer_T245 39420-39536 Sentence denotes It would be irresponsible to claim a high inactivation rate for a pathogenic bioaerosol without substantial testing.
TextSentencer_T245 39420-39536 Sentence denotes It would be irresponsible to claim a high inactivation rate for a pathogenic bioaerosol without substantial testing.
TextSentencer_T246 39537-39594 Sentence denotes Even with substantial testing, design failures may occur.
TextSentencer_T246 39537-39594 Sentence denotes Even with substantial testing, design failures may occur.
TextSentencer_T247 39595-39851 Sentence denotes Although many laboratory studies have been conducted to analyze the efficacy of UVGI for numerous microorganisms in a range of temperature and humidity conditions, little has been done to evaluate the practical application of UVGI in health care buildings.
TextSentencer_T247 39595-39851 Sentence denotes Although many laboratory studies have been conducted to analyze the efficacy of UVGI for numerous microorganisms in a range of temperature and humidity conditions, little has been done to evaluate the practical application of UVGI in health care buildings.
TextSentencer_T248 39852-40052 Sentence denotes 3 In fact, Beggs et al 58 concluded that ''the knowledge base that exists on UVGI and its application is relatively small, and health care authorities have few guidelines on which to make decisions.''
TextSentencer_T248 39852-40052 Sentence denotes 3 In fact, Beggs et al 58 concluded that ''the knowledge base that exists on UVGI and its application is relatively small, and health care authorities have few guidelines on which to make decisions.''
TextSentencer_T249 40053-40209 Sentence denotes As discussed earlier, potentially infectious droplet nuclei emitted from an infected host might be coated with mucus and consist of more than one bacterium.
TextSentencer_T249 40053-40209 Sentence denotes As discussed earlier, potentially infectious droplet nuclei emitted from an infected host might be coated with mucus and consist of more than one bacterium.
TextSentencer_T250 40210-40379 Sentence denotes Study bacteria, aerosolized in deionized water and lacking a mucus coating, may be more sensitive to UVGI compared with bacteria in droplet nuclei from an infected host.
TextSentencer_T250 40210-40379 Sentence denotes Study bacteria, aerosolized in deionized water and lacking a mucus coating, may be more sensitive to UVGI compared with bacteria in droplet nuclei from an infected host.
TextSentencer_T251 40380-40481 Sentence denotes 44 Installation and maintenance UVGI is associated with human health risks and unpredictable results.
TextSentencer_T251 40380-40481 Sentence denotes 44 Installation and maintenance UVGI is associated with human health risks and unpredictable results.
TextSentencer_T252 40482-40568 Sentence denotes UV rays can cause harm to building occupants if not properly installed and maintained.
TextSentencer_T252 40482-40568 Sentence denotes UV rays can cause harm to building occupants if not properly installed and maintained.
TextSentencer_T253 40569-40730 Sentence denotes Installation techniques widely vary among manufacturers and currently are not regulated by a governing body to ensure proper efficacy of UVGI after installation.
TextSentencer_T253 40569-40730 Sentence denotes Installation techniques widely vary among manufacturers and currently are not regulated by a governing body to ensure proper efficacy of UVGI after installation.
TextSentencer_T254 40731-40835 Sentence denotes UVGI lamp manufacturers (eg, Philips PLD), acknowledge that some important information is not available.
TextSentencer_T254 40731-40835 Sentence denotes UVGI lamp manufacturers (eg, Philips PLD), acknowledge that some important information is not available.
TextSentencer_T255 40836-41164 Sentence denotes For example, regarding to the sizing of UV lamps for installation in ductwork systems, a Philips technical document on UV disinfection states that ''in the calculation.it should be emphasized that it results only in a rough estimation; we did not incorporate the possible effects of humidity and temperature on the killing rate.
TextSentencer_T255 40836-41164 Sentence denotes For example, regarding to the sizing of UV lamps for installation in ductwork systems, a Philips technical document on UV disinfection states that ''in the calculation.it should be emphasized that it results only in a rough estimation; we did not incorporate the possible effects of humidity and temperature on the killing rate.
TextSentencer_T256 41165-41433 Sentence denotes Philips is not a specialist in that field; we always advise to contact qualified authorities to evaluate the bacteriological aspects.'' 59 The use of CFD models and improved distribution studies on UVGI lamps and fixtures is moving the industry in the right direction.
TextSentencer_T256 41165-41433 Sentence denotes Philips is not a specialist in that field; we always advise to contact qualified authorities to evaluate the bacteriological aspects.'' 59 The use of CFD models and improved distribution studies on UVGI lamps and fixtures is moving the industry in the right direction.
TextSentencer_T257 41434-41600 Sentence denotes The CFD models characterize the room and air distribution in coordination with any UVGI systems applied within the space to evaluate the effectiveness quantitatively.
TextSentencer_T257 41434-41600 Sentence denotes The CFD models characterize the room and air distribution in coordination with any UVGI systems applied within the space to evaluate the effectiveness quantitatively.
TextSentencer_T258 41601-41814 Sentence denotes 3 For UVGI applications in AHU and ductwork, maintenance personnel may be at increased risk even if their exposure time to the UVGI irradiation is short, because they will be in close proximity to the UVGI source.
TextSentencer_T258 41601-41814 Sentence denotes 3 For UVGI applications in AHU and ductwork, maintenance personnel may be at increased risk even if their exposure time to the UVGI irradiation is short, because they will be in close proximity to the UVGI source.
TextSentencer_T259 41815-41889 Sentence denotes Service personnel and occupants are at risk without special care measures.
TextSentencer_T259 41815-41889 Sentence denotes Service personnel and occupants are at risk without special care measures.
TextSentencer_T260 41890-41962 Sentence denotes Service staff need to ensure that the system is turned off when working.
TextSentencer_T260 41890-41962 Sentence denotes Service staff need to ensure that the system is turned off when working.
TextSentencer_T261 41963-42077 Sentence denotes The need to wear protective clothing and eyewear should be stressed to prevent any possibility of harm to workers.
TextSentencer_T261 41963-42077 Sentence denotes The need to wear protective clothing and eyewear should be stressed to prevent any possibility of harm to workers.
TextSentencer_T262 42078-42215 Sentence denotes Room occupants may be exposed to higher doses of UVGI irradiation if the fixtures are not located or installed properly within the space.
TextSentencer_T262 42078-42215 Sentence denotes Room occupants may be exposed to higher doses of UVGI irradiation if the fixtures are not located or installed properly within the space.
TextSentencer_T263 42216-42328 Sentence denotes Health care providers are at a greater risk because they occupy the space for longer periods than most patients.
TextSentencer_T263 42216-42328 Sentence denotes Health care providers are at a greater risk because they occupy the space for longer periods than most patients.
TextSentencer_T264 42329-42515 Sentence denotes UVGI overexposure has the potential to cause unpleasant eye and skin irritations; however, these effects appear to be temporary and have involved no known long-term consequences to date.
TextSentencer_T264 42329-42515 Sentence denotes UVGI overexposure has the potential to cause unpleasant eye and skin irritations; however, these effects appear to be temporary and have involved no known long-term consequences to date.
TextSentencer_T265 42516-42518 Sentence denotes 60
TextSentencer_T265 42516-42518 Sentence denotes 60
TextSentencer_T266 42520-42756 Sentence denotes Additional areas of research needed to determine the most effective upper-room UVGI systems include UVGI measurements, air mixing, the effect of low humidity, microbial sensitivity, and testing and validation of upper-room UVGI systems.
TextSentencer_T266 42520-42756 Sentence denotes Additional areas of research needed to determine the most effective upper-room UVGI systems include UVGI measurements, air mixing, the effect of low humidity, microbial sensitivity, and testing and validation of upper-room UVGI systems.
TextSentencer_T267 42757-42959 Sentence denotes More research is also needed on the ability of UVGI systems to kill or inactivate microorganisms in respirable droplet nuclei of variable sizes and droplet nuclei coated with actual or simulated sputum.
TextSentencer_T267 42757-42959 Sentence denotes More research is also needed on the ability of UVGI systems to kill or inactivate microorganisms in respirable droplet nuclei of variable sizes and droplet nuclei coated with actual or simulated sputum.
TextSentencer_T268 42960-43267 Sentence denotes 5 Methods for determining whether existing room air mixing is sufficient for UVGI effectiveness are needed, and research should explore whether the use of mixing fans has a negative impact on the intended design of the mechanical ventilation systems or a negative impact on other infection control measures.
TextSentencer_T268 42960-43267 Sentence denotes 5 Methods for determining whether existing room air mixing is sufficient for UVGI effectiveness are needed, and research should explore whether the use of mixing fans has a negative impact on the intended design of the mechanical ventilation systems or a negative impact on other infection control measures.
TextSentencer_T269 43268-43403 Sentence denotes There is some indication that low RH (,25%) might adversely affect the ability of UVGI systems to kill or inactivate airborne bacteria.
TextSentencer_T269 43268-43403 Sentence denotes There is some indication that low RH (,25%) might adversely affect the ability of UVGI systems to kill or inactivate airborne bacteria.
TextSentencer_T270 43404-43447 Sentence denotes Additional research is needed in this area.
TextSentencer_T270 43404-43447 Sentence denotes Additional research is needed in this area.
TextSentencer_T271 43448-43584 Sentence denotes Research in full-scale rooms to better ascertain the effects of high humidity (eg, 80% RH) on airborne microorganisms is needed as well.
TextSentencer_T271 43448-43584 Sentence denotes Research in full-scale rooms to better ascertain the effects of high humidity (eg, 80% RH) on airborne microorganisms is needed as well.
TextSentencer_T272 43585-43871 Sentence denotes Experimental research has indicated that mechanical ventilation of up to 6 ACH does not have a significant effect on the effectiveness of upper-room UVGI systems; studies are needed to examine whether mechanical ventilation .6 ACH decreases the effectiveness of upper-room UVGI systems.
TextSentencer_T272 43585-43871 Sentence denotes Experimental research has indicated that mechanical ventilation of up to 6 ACH does not have a significant effect on the effectiveness of upper-room UVGI systems; studies are needed to examine whether mechanical ventilation .6 ACH decreases the effectiveness of upper-room UVGI systems.
TextSentencer_T273 43872-43982 Sentence denotes Tests to determine the relative sensitivity of microorganisms to UVGI are not standardized among laboratories.
TextSentencer_T273 43872-43982 Sentence denotes Tests to determine the relative sensitivity of microorganisms to UVGI are not standardized among laboratories.
TextSentencer_T274 43983-44102 Sentence denotes Laboratory testing guidelines are needed to ensure that these tests are reproducible and reflect real-world situations.
TextSentencer_T274 43983-44102 Sentence denotes Laboratory testing guidelines are needed to ensure that these tests are reproducible and reflect real-world situations.
TextSentencer_T275 44103-44194 Sentence denotes Laboratory tests of the efficacy of UVGI upper-room systems should be standardized as well.
TextSentencer_T275 44103-44194 Sentence denotes Laboratory tests of the efficacy of UVGI upper-room systems should be standardized as well.
TextSentencer_T276 44195-44314 Sentence denotes Protocols for testing and validating upper-room UVGI systems are needed to ensure that the systems perform as designed.
TextSentencer_T276 44195-44314 Sentence denotes Protocols for testing and validating upper-room UVGI systems are needed to ensure that the systems perform as designed.
TextSentencer_T277 44315-44316 Sentence denotes 1
TextSentencer_T277 44315-44316 Sentence denotes 1
TextSentencer_T278 44317-44445 Sentence denotes Guidelines are needed to determine the most practical method for planning effective UVGI systems in a variety of rooms or areas.
TextSentencer_T278 44317-44445 Sentence denotes Guidelines are needed to determine the most practical method for planning effective UVGI systems in a variety of rooms or areas.
TextSentencer_T279 44446-44641 Sentence denotes Theoretically, CFD modeling can be used to evaluate many of the variables associated with installing an upper-room UVGI system and provide an estimate of the UVGI dose received by droplet nuclei.
TextSentencer_T279 44446-44641 Sentence denotes Theoretically, CFD modeling can be used to evaluate many of the variables associated with installing an upper-room UVGI system and provide an estimate of the UVGI dose received by droplet nuclei.
TextSentencer_T280 44642-44846 Sentence denotes Experiments involving photoreactivation of microorganisms in full-scale test rooms should be conducted, as should tests of the effectiveness of UVGI on airborne bacteria over a wide range of temperatures.
TextSentencer_T280 44642-44846 Sentence denotes Experiments involving photoreactivation of microorganisms in full-scale test rooms should be conducted, as should tests of the effectiveness of UVGI on airborne bacteria over a wide range of temperatures.
TextSentencer_T281 44847-44959 Sentence denotes In real-world situations, potentially infectious droplet nuclei will vary in size and may be coated with sputum.
TextSentencer_T281 44847-44959 Sentence denotes In real-world situations, potentially infectious droplet nuclei will vary in size and may be coated with sputum.
TextSentencer_T282 44960-45021 Sentence denotes Both of these factors can decrease the effectiveness of UVGI.
TextSentencer_T282 44960-45021 Sentence denotes Both of these factors can decrease the effectiveness of UVGI.
TextSentencer_T283 45022-45306 Sentence denotes Although some laboratory research has been done to evaluate these parameters, 34, 44, 61 more work is needed to further characterize microbial susceptibility to UVGI based on the size of respirable (up to 5 mm) droplet nuclei and droplet nuclei coated with actual or simulated sputum.
TextSentencer_T283 45022-45306 Sentence denotes Although some laboratory research has been done to evaluate these parameters, 34, 44, 61 more work is needed to further characterize microbial susceptibility to UVGI based on the size of respirable (up to 5 mm) droplet nuclei and droplet nuclei coated with actual or simulated sputum.
TextSentencer_T284 45307-45582 Sentence denotes Data for real-world applications As this and previous literature reviews have shown, although numerous studies address the efficacy of UVGI, there remains a lack of definitive epidemiologic data demonstrating that these systems prevent HAIs endemic to health care facilities.
TextSentencer_T284 45307-45582 Sentence denotes Data for real-world applications As this and previous literature reviews have shown, although numerous studies address the efficacy of UVGI, there remains a lack of definitive epidemiologic data demonstrating that these systems prevent HAIs endemic to health care facilities.
TextSentencer_T285 45583-45716 Sentence denotes Also lacking is objective, reproducible evidence of improved energy efficiency of coils and fans with UVGI systems installed in AHUs.
TextSentencer_T285 45583-45716 Sentence denotes Also lacking is objective, reproducible evidence of improved energy efficiency of coils and fans with UVGI systems installed in AHUs.
TextSentencer_T286 45717-45930 Sentence denotes The efficacy of an upper-room UVGI application depends strongly on sufficient exposure of microorganisms to UV-C, which can occur if there is good mixing of upper and lower air in the room or area where installed.
TextSentencer_T286 45717-45930 Sentence denotes The efficacy of an upper-room UVGI application depends strongly on sufficient exposure of microorganisms to UV-C, which can occur if there is good mixing of upper and lower air in the room or area where installed.
TextSentencer_T287 45931-46151 Sentence denotes Furthermore, there are many marketing claims suggesting that such systems, as well as mobile systems, will protect occupants against emerging diseases such as SARS CoV, influenza, M tuberculosis, and bioterrorism agents.
TextSentencer_T287 45931-46151 Sentence denotes Furthermore, there are many marketing claims suggesting that such systems, as well as mobile systems, will protect occupants against emerging diseases such as SARS CoV, influenza, M tuberculosis, and bioterrorism agents.
TextSentencer_T288 46152-46307 Sentence denotes These claims have not been substantiated by the existing data, however, and must be weighed against the many variables discussed in this literature review.
TextSentencer_T288 46152-46307 Sentence denotes These claims have not been substantiated by the existing data, however, and must be weighed against the many variables discussed in this literature review.
TextSentencer_T289 46308-46523 Sentence denotes For TB, there is ample laboratory and reasonable evidence from animal studies, but the key question remains the relative role of UVGI in the context of the hierarchy of controls to prevent health care-associated TB.
TextSentencer_T289 46308-46523 Sentence denotes For TB, there is ample laboratory and reasonable evidence from animal studies, but the key question remains the relative role of UVGI in the context of the hierarchy of controls to prevent health care-associated TB.
TextSentencer_T290 46524-46637 Sentence denotes Some of the agents that might be used for bioterrorism, such as anthrax spores, are not very susceptible to UV-C.
TextSentencer_T290 46524-46637 Sentence denotes Some of the agents that might be used for bioterrorism, such as anthrax spores, are not very susceptible to UV-C.
TextSentencer_T291 46638-46795 Sentence denotes Because the clinical effectiveness of UV systems may vary, UVGI is not recommended for air management before air recirculation from airborne isolation rooms.
TextSentencer_T291 46638-46795 Sentence denotes Because the clinical effectiveness of UV systems may vary, UVGI is not recommended for air management before air recirculation from airborne isolation rooms.
TextSentencer_T292 46796-46918 Sentence denotes It also is not recommended as a substitute for HEPA filtration, local exhaust of air to the outside, or negative pressure.
TextSentencer_T292 46796-46918 Sentence denotes It also is not recommended as a substitute for HEPA filtration, local exhaust of air to the outside, or negative pressure.
TextSentencer_T293 46919-47077 Sentence denotes The use of UV lamps and HEPA filtration in a single unit offers only minimal infection control benefits over those provided by the use of a HEPA filter alone.
TextSentencer_T293 46919-47077 Sentence denotes The use of UV lamps and HEPA filtration in a single unit offers only minimal infection control benefits over those provided by the use of a HEPA filter alone.
TextSentencer_T294 47078-47240 Sentence denotes Duct systems with UVGI are not recommended as a substitute for HEPA filters when the air from isolation rooms must be recirculated to other areas of the facility.
TextSentencer_T294 47078-47240 Sentence denotes Duct systems with UVGI are not recommended as a substitute for HEPA filters when the air from isolation rooms must be recirculated to other areas of the facility.
TextSentencer_T295 47241-47368 Sentence denotes Regular maintenance of UVGI systems, involving keeping the bulbs free of dust and replacing old bulbs as necessary, is crucial.
TextSentencer_T295 47241-47368 Sentence denotes Regular maintenance of UVGI systems, involving keeping the bulbs free of dust and replacing old bulbs as necessary, is crucial.
TextSentencer_T296 47369-47451 Sentence denotes Safety issues associated with the use of UVGI systems are described in guidelines.
TextSentencer_T296 47369-47451 Sentence denotes Safety issues associated with the use of UVGI systems are described in guidelines.
TextSentencer_T297 47452-47657 Sentence denotes When UVGI units are required for air cleaning, as demonstrated by a risk assessment of the AII area, the units should be installed in the exhaust air ducts of the HVAC system to supplement HEPA filtration.
TextSentencer_T297 47452-47657 Sentence denotes When UVGI units are required for air cleaning, as demonstrated by a risk assessment of the AII area, the units should be installed in the exhaust air ducts of the HVAC system to supplement HEPA filtration.
TextSentencer_T298 47658-47927 Sentence denotes When UVGI is used as a supplemental engineering control, fixtures should be installed on the wall near the ceiling or suspended from the ceiling as an upper-air unit, in the air-return duct of an AII room, or in designated enclosed areas or booths for sputum induction.
TextSentencer_T298 47658-47927 Sentence denotes When UVGI is used as a supplemental engineering control, fixtures should be installed on the wall near the ceiling or suspended from the ceiling as an upper-air unit, in the air-return duct of an AII room, or in designated enclosed areas or booths for sputum induction.
TextSentencer_T299 47928-48171 Sentence denotes In summing up the role of UVGI in today's health care facilities, UVGI should continue to be viewed not a routine replacement for ventilation, but rather as a supplement when needed under the conditions and parameters described in this review.
TextSentencer_T299 47928-48171 Sentence denotes In summing up the role of UVGI in today's health care facilities, UVGI should continue to be viewed not a routine replacement for ventilation, but rather as a supplement when needed under the conditions and parameters described in this review.
TextSentencer_T300 48172-48293 Sentence denotes It does not appear to have a role in the OR, where air changes are well above 4-6 ACH, or in properly designed AII rooms.
TextSentencer_T300 48172-48293 Sentence denotes It does not appear to have a role in the OR, where air changes are well above 4-6 ACH, or in properly designed AII rooms.
TextSentencer_T301 48294-48427 Sentence denotes Many questions remain regarding how to achieve a balance between utility and safety; hopefully, the necessary research will continue.
TextSentencer_T301 48294-48427 Sentence denotes Many questions remain regarding how to achieve a balance between utility and safety; hopefully, the necessary research will continue.