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Resources and Support for the Use of Upper Air Ultraviolet Germicidal Irradiation (UVGI or UV)

The following offers just some readily available resources on the use of UV to disinfect the air and, more specifically, the use of upper room UV.

“There is a long history of investigations concluding that, if used properly, UVGI can be safe and highly effective in disinfecting the air, thereby preventing transmission of a variety of airborne infections.

The History of Ultraviolet Germicidal Irradiation for Air Disinfection

In this public health report author Nicholas G. Reed, with the U.S. Army Center for Health Promotion and Preventive Medicine, Laser/Optical Radiation Program, Aberdeen Proving Ground, MD, USA, tracks the “long history” of using UV as “an established means of disinfection and can be used to prevent the spread of certain infectious diseases.” The informative and interesting report includes its historical use including how, between 1937-1941, upper room UVGI was “successfully used” to “prevent the epidemic spread of measles among children in suburban Philadelphia day schools, where infection outside of school was unlikely.”

“Research indicates that an appropriately designed and maintained upper-room UVGI system may kill or inactivate airborne TB bacteria and increase the protection afforded to healthcare workers while maintaining a safe level of UVGI in the occupied lower portion of the room.”

Environmental Control for Tuberculosis: Basic Upper-Room Ultraviolet Germicidal Irradiation Guidelines for Healthcare Settings

Published by the Department of Health and Human Services (HHS), with the Centers for Disease and Prevention (CDC) and the National Institute for Occupational Safety and Health (NIOSH), these guidelines are “designed to provide information to healthcare managers, facility designers, engineers, and industrial hygienists on the parameters necessary to install and maintain an effective upper-room UVGI system.” As described in the document: “The use of ultraviolet germicidal irradiation (UVGI) in the upper portion of rooms or areas is an environmental control measure that may be effective in killing or inactivating air-borne M. tuberculosis generated by persons with unknown or unsuspected infectious TB.”

“Control of seasonal influenza has for decades relied on large-droplet precautions even though there is evidence suggesting a far greater importance for airborne transmission by small particles. For instance, a 1959 study of influenza prevention in a Veterans Administration nursing home identified an 80% reduction in influenza in staff and patients through the use of upper room ultraviolet germicidal irradiation (UVGI)…This suggests that air currents to the higher-room areas where the UVGI was present carried the airborne infectious particles, and they were inactivated. The inactivated (noninfectious) particles were therefore unable to infect staff and patients in control areas with UVGI, as compared to areas without UVGI.”

ASHRAE Position Document on Airborne Infectious Diseases

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) finds UVGI (upper room, in-room, and in the airstream) as one of its “strategies of interest.” The organization also includes in its position paper, suggested “emergency planning” measures for engineers. As described in the paper:

“Four worldwide (pandemic) outbreaks of influenza occurred in the twentieth century: 1918, 1957, 1968, and 2009 (BOMA 2012). Not classified as true pandemics are three notable epidemics: a pseudopandemic in 1947 with low death rates, an epidemic in 1977 that was a pandemic in children, and an abortive epidemic of swine influenza in 1976 that was feared to have pandemic potential. The most recent H1N1 pandemic in 2009 resulted in thousands of deaths worldwide but was nowhere near the death toll of the 1918 Spanish flu, which was the most serious pandemic in recent history and was responsible for the deaths of an estimated more than 50 million people. There have been about three influenza pandemics in each century for the last 300 years. If a new outbreak occurs and is caused by a microorganism that spreads by the airborne route, fast action affecting building operations will be needed. Some biological agents that may be used in terrorist attacks are addressed elsewhere (USDHHS 2002, 2003). Engineers can support emergency planning by understanding the design, operations, and maintenance adequacy of buildings for which they are responsible and helping emergency planners mitigate vulnerabilities or develop interventions. For instance, there may be means to increase dilution ventilation, increase relative humidity, or quickly apply upper room UVGI in an emergency room, transportation waiting area, shelter, jail, and crowded entries to buildings in an emergency…”

Further, in its recommendations, ASHRAE advises:

Some infectious diseases are transmitted through inhalation of airborne infectious particles, which can be disseminated through buildings by pathways that include ventilation systems. Airborne infectious disease transmission can be reduced using dilution ventilation; directional ventilation; in-room airflow regimes; room pressure differentials; personalized ventilation; and source capture ventilation, filtration, and UVGI.”

Among its specific recommendations:

Building designers, owners, and operators should give high priority to enhancing well-designed, installed, commissioned, and maintained HVAC systems with supplemental filtration, UVGI, and, in some cases, to additional or more effective ventilation to the breathing zone. Filtration and UVGI can be applied in new buildings at moderate additional cost and can be applied quickly in existing building systems to decrease the severity of acute disease outbreaks.”