In honor of the first day of school in Michigan tomorrow, I wanted to bring attention to an article in the Wall Street Journal that reinforces an important concept for COVID-19 safety in classrooms. It is that by simply increasing ventilation and airflow in classrooms, respiratory clouds that contain the SARS-CoV-2 virus can be disrupted before they can cause infection.
It is a concept that seems to have been somewhat forgotten about in the return to school.
Most recommendations focused on social distancing and surface decontamination. No one really thought about how to keep people safe when they had to be in groups. Scientists and mechanical engineers have recently issuing recommendations to schools and businesses that wish to reopen for how often indoor air needs to be replaced, as well as guidelines for the fans, filters and other equipment needed to meet the goals.
This concept is being driven by research findings that suggest that most coronavirus transmission is the airborne aerosols. In fact, focusing on masks and air flow are clearly the most important things in preventing transmission of COVID-19.
Most experts now suggest that public spaces, like standard classrooms, should have air replaced with clean air between four to six times an hour to dilute Covid-19 particles that might be coughed or breathed into the air.
That can be done, aerosol scientists say, through strategies that introduce outdoor air and filter indoor contaminants. Those include opening windows and doors, installing window fans, using portable air purifiers with high-efficiency particulate air, or HEPA, filters and upgrading heating, ventilation, and air-conditioning systems to meet standards.
As winter comes to the northern states, heating units and portable HEPA filters will become crucial to maintaining airflow given that outside air cannot be freely exchanged (at least without frostbite). While HEPA air filters are not inexpensive, they are cheaper than hospitalizations and would be a great alternative to leaving working parents in the lurch!
Pandemic Pondering 
We believe that our daughter’s 45 days of paroxysmal sneezing, with sudden onset, severe ragweed allergy may have actually been precipitated or at least aggravated by the fresh air being filtered hourly into her school classroom? The building superintendent said that under a federal “Life Safety” program several years ago, the new building was required to be zoned and X amount of fresh air had to be pumped inside each classroom at a specific rate? She was on strict orders from her Allergist/Immunologist to avoid all outside recesses. The building superintendent finally suggested that any room where she would be present, would be zoned off for no fresh air. I guess where I am going with this, is that means for fresh air is already present in most modern day educational facilities? Thank you for continuing this blog. We learn daily from your posts. We are probably your biggest fans, next to Biscuit!
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I appreciate your daughters situation. HEPA filters remove pollen.
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Can referenced HEPA filters be installed in the blower systems of most residential furnaces, and, if so, what would be an estimated cost to do so? What is the availability of such HEPA filters?
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