Peer Review Document: Policy Statement on Layered Risk Reduction to Reduce Exposures to COVID-19

Posted · 4 Comments

The following is a simple statement of policy on using layered risk reduction when managing an indoor environment to reduce exposures to COVID-19. This statement was developed by the Board of Directors in the Fall of 2021, and is now undergoing a process of peer review and comment. Please read through the document, and post your thoughts and comments in the message box below. Thank you for your input!

MIAQC DRAFT Policy Statement on Layered Risk Reduction to Reduce Exposures to COVID-19

Whereas the SARS-CoV-2, the virus that causes the illness we know as COVID-19, is spread through: 

  1. Inhalation. Virus particles emitted into the air when an infected person breathes, speaks, sings, coughs, or sneezes can be inhaled by a non-infected person.
  2. Close Contact. When a non-infected person has close personal contact with an infected person, such as touching or shaking hands, and then touches their nose, mouth, or eye.
  3. Surfaces.  When a non-infected person touches an object or surface with active virus on it, then touches their mouth, nose, or eye.

And whereas the SARS-CoV-2 virus particles can remain airborne for undetermined distances:

  1. The SARS-CoV-2 respiratory droplets vary in size.  Larger droplets will fall out of the air quickly.  Smaller virus particles (also called aerosols) can travel farther.  How far a virus particle can travel depends on particle size and available air flow in the space.

Therefore, the Maine Indoor Air Quality Council supports practices that reduce the risk of virus transmission indoors, whether it is the illness we know as COVID-19 or other airborne diseases.  Specifically, the Council supports the implementation of “layered risk reduction”:  the practice of using a variety of measures to create greater risk reduction collectively than each individual measure can produce on its own.

The elements of layered risk reduction for COVID-19 include:

  1. Personal Protections:  wearing masks, physical distancing, handwashing and/or sanitizing, and vaccination
  2. Ventilation to remove virus particles from the indoor environment
  3. Filtration to remove virus particles from the indoor environment
  4. Surface cleaning to remove/disinfect active virus particles that have settled onto surfaces and commonly touched areas
4 Responses to "Peer Review Document: Policy Statement on Layered Risk Reduction to Reduce Exposures to COVID-19"
  1. Christy says:

    Thank you for taking the time and effort to review our guidance document on layered risk reduction to reduce exposures to COVID-19 when indoors. Your input and expertise is greatly valued. Please include your company name and profession in your post. – Christy Crocker, Executive Director, Maine Indoor Air Quality Council

    • William Turner says:

      Perhaps this statement could be improved by recommending ventilation rates as recommended by ASHRAE, and some suggestion of Filtration by ASHRAE or others. ?

      • Rickl Karg says:

        Use: “. . .collectivly create greater risk reduction. . .” rather than “. . .create greater risk reduction collectively. . .” This works better for me, although I think it is primarily a matter of style.

        I think Bill T. suggestion is good, especially for filtration. ASHRAE recommends at least MERV 13 for permanent filter installations and MERV 13 or HEPA for portable air cleaners. However, for ventilation, the recommendations are not as clear and, thus, probably should not be stated.

        • Chris Rioux says:

          Given that the available scientific data on the efficacy of mask wearing indicates little to no benefit, and the recommendation is still being hotly debated by qualified medical professionals, and given that the personal distancing of 6′ used during the pandemic was a “practical random” distance not based on the real rate of droplet spread, and given the shifting efficacy of the available vaccines is still not certain, the line on personal protection is of little practical use as a guidance tool. The focus on ventilation, filtration and surface care are of practical use if they regard specific or quantifiable information.

          Comments are closed.

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