The US Environmental Protection Agency’s (EPA’s) Indoor Air Quality (IAQ) program offers guidance how to use ventilation to help prevent the spread of respiratory viruses in “indoor public spaces” including offices and commercial locations. As north America approaches winter months when more people spend more time indoors, it’s a good time to review these suggestions. The rest of this note summarizes EPA guidance.
EPA recommends “multi-layered” approaches
EPA reminds that there are many types of airborne respiratory viruses, including the COVID-19 virus, influenza (flu) and respiratory syncytial virus (RSV). They can spread more easily indoors than outdoors, since their concentration can build up indoors and people are often closer to each other. EPA identifies several complementary approaches to address IAQ and possible virus contamination.
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Ventilation
This involves installation/configuration and operation of appropriate equipment, including:
- Increase outside-air ventilation to the maximum extent practical (although increased airflow may produce issues when outside ambient air is particularly cold or hot, requiring additional temperature management).
- Adjust or reconfigure air flows to minimize flows between people – e.g., redirect airflows to prevent air from blowing directly from person to person and/or exhausting restrooms directly to the outdoors.
Note that ventilation is also subject to regulation by the Occupational Safety and Health Administration (OSHA) Respiratory Protection Standard (29 CFR 1910.134) (which I wrote about HERE), and OSHA also provides multi-layered recommendations (I wrote about OSHA’s advice to consider ventilation during the COVID-19 pandemic HERE). The Centers for Disease Control and Prevention (CDC) (including its sub-unit National Institute for Occupational Safety and Health (NIOSH)) for workplace issues) also provide technical guidance; EPA cites CDC’s recommendation to achieve 5 ACH (Air Changes per Hour) using outdoor air ventilation alone, or 5 eACH (Equivalent Air Changes per Hour) using a combination of ventilation from outdoor air, filtration, and other air treatment.
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Filtration and supplemental air cleaning
In addition to improving ventilation, EPA recommends that owners and occupants consider filtration and supplemental air cleaning to reduce the occurrence of viral particles in indoor air. These measures can include:
- filter air that is recirculated through heating, ventilation and air condition (HVAC) systems to remove aerosols and particulates - upgrade HVAC filters (MERV ratings (Minimum Efficiency Reporting Value) calculate air filters’ effectiveness in capturing particles; MERV 16 is highest, but some HVAC systems may only accommodate lower-MERV technology).
- Place portable air cleaners in areas that are hard to ventilate with outside air, or have high density or occupancy.
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Air treatment
Devices can be installed to kill pathogens, including Upper Room Ultraviolet Germicidal Irradiation (UVGI), or technologies that rely on the addition of chemicals, charged ions, or photolysis. Depending on the equipment and location, some of these may adversely impact indoor air (e.g., by resulting in ozone concentrations).
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Administrative controls
Administrative controls change workplace practices to change how space is used. These may include:
- Practices designed to reduce crowding or occupancy such as telework, staggered schedules, remote/video meetings, etc.
- Limiting the use of small spaces that are shared by multiple people, including meeting rooms, laundry rooms, and lobbies.
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Enhanced cleaning and disinfection
Although surface cleaning and disinfection is most obviously useful against pathogens that spread by contact, cleaning surfaces (especially frequently touched ones) and being diligent about hygiene when an occupant may be sick with a respiratory virus can help prevent the spread of illness.
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Reconfiguring building spaces and furnishings
It may also be practical to reconfigure building spaces and furnishings, to increase the space or separation between individuals indoors, minimize direct air flow between people, and reduce their interaction in high-traffic areas of buildings. Reconfiguration efforts may include:
- Reconfiguration of building layouts and/or of individual rooms.
- Reorientation of office furniture or cubicles (e.g., reorient adjoining workstations so employees do not face each other).
What happens now?
To copy a popularized phrase: Winter is coming (and may have arrived before you read this note). As more workplaces and public spaces tighten up for cold weather, it’s useful to review workplace ventilation and HVAC systems.
Self-Assessment Checklist
Has the organization assessed its operations to evaluate workplace ventilation and air quality?
If so, has this evaluation included consideration of equipment, administrative/procedural, and structural circumstances and how changes may reduce airborne transmission of viruses and other contagions in the workplace?
If so, has the organization implemented measures considered helpful?
Where Do I Go For More Information?
- EPA –
- webpage “Ventilation and Respiratory Viruses
- webpage “Preventing the Spread of Respiratory Viruses in Public Indoor Spaces”
- OSHA –
- webpage “Respiratory Protection”
About the Author
Jon Elliott is President of Touchstone Environmental and has been a major contributor to STP’s product range for over 30 years.
Mr. Elliott has a diverse educational background. In addition to his Juris Doctor (University of California, Boalt Hall School of Law, 1981), he holds a Master of Public Policy (Goldman School of Public Policy [GSPP], UC Berkeley, 1980), and a Bachelor of Science in Mechanical Engineering (Princeton University, 1977).
Mr. Elliott is active in professional and community organizations. In addition, he is a past chairman of the Board of Directors of the GSPP Alumni Association, and past member of the Executive Committee of the State Bar of California's Environmental Law Section (including past chair of its Legislative Committee).
You may contact Mr. Elliott directly at: tei@ix.netcom.com