State-level guidance regarding air filtration systems in hospitals and healthcare facilities in light of COVID-19 appears to vary greatly over the last six months. Some states still do not mention filtration systems at all, while others merely point to national organizations for guidance. A number of states specify in detail things to consider specifically for dentists. The strictest measures found were in the State of California, which regulates COVID-19 under the requirements of the state’s Aerosol Transmissible Diseases standard.
References to National Organizations
- A number of states list links to CDC guidelines regarding air control and filtration, including the Iowa Department of Public Health.
- Some states, such as the Arizona Department of Health Services, make no specific filtration recommendations “in accordance with the World Health Organization and the low risk of airborne transmission.”
- Other states, such as the Wyoming Department of Health, do not mention filtration systems at all, yet provide a link to the CDC for additional guidance.
State of California
- The State of California Department of Industrial Relations calls COVID-19 an airborne infectious disease, and as such it is regulated under the requirements of the The Aerosol Transmissible Diseases (ATD) standard (California Code of Regulations, title 8, section 5199).
- The ATD standard provides strict guidelines for hospitals and healthcare facilities. Specifically regarding air circulation, the following criteria must be observed: isolate infected persons in airborne infection isolation rooms, conduct high-hazard procedures in airborne infection isolation rooms, ventilate rooms to a removal efficiency of 99.9% in accordance with this CDC table, use airtight barriers to eliminate worker exposure, and use local exhaust ventilation, HEPA air filtration and air disinfection in patient areas.
Multnomah County (Oregon)
- The county page highlights in bold that “experts don’t yet fully understand the role that HVAC systems play in transmitting COVID-19 indoors.” However, it also states that “most experts agree that a state-of-the-art, modern HVAC system that exchanges outdoor air for indoor air and has excellent filtration reduces the risk of spreading COVID-19.”
- The county recommends that older buildings with systems that recirculate air do the following: open windows, use portable air purifiers with HEPA filters, and use “filters with a Minimum Efficiency Reporting Value (MERV) rating of 13 or higher in the building’s HVAC system.”
- The county also provides links to guidelines published by The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), and CDC.
Minnesota Department of Health
- The Minnesota Department of Health provides a number of links on their website for further information regarding air filtration guidelines.
- The website offers general information about indoor air considerations, which can be applied in a number of settings.
- The Department of Health offers detailed and lengthy guidelines for dealing with aerosol-generating procedures, which may be specifically applied to dentists.
- An additional article by the state provides guidance with considerations in regard to HVAC and fans in long-term care facilities.
Pennsylvania Department of Health
- The Pennsylvania Department of Health provides detailed measures to follow in dental settings, and outlines specific guidelines from the CDC regarding ventilation systems.
- The website states, “CDC does not provide guidance on the decontamination of building heating, ventilation, and air conditioning (HVAC) systems potentially exposed to SARS-CoV-2. To date, CDC has not identified confirmatory evidence to demonstrate that viable virus is contaminating these systems.”
- The website makes recommendations pertaining to the proper maintenance of HVAC systems, including the use of portable high-efficiency particulate air (HEPA) air filtration units when performing high aerosol generating procedures.
- Additionally, the website recommends using an upper-room ultraviolet germicidal irradiation (UVGI) to increase ventilation and air cleaning.