Earlier this year the Centers for Disease Control (CDC) issued COVID-19 recommendations for schools and childcare facilities. The most underutilized anti-COVID strategy, or maybe just the least talked about, is air hygiene. Compared to the very visible and highly politicized protective masks, clean air is pretty boring. But now, especially with everyone agitated about how to make schools safe, air is having its moment.
Open windows and portable air cleaning machines are useful. While earlier efforts were praiseworthy for their intention, investment in building-wide filtration systems is certainly more worthwhile than erecting acres of plexiglass barriers.
Practical suggestions and crazy dreams
This article from the CDC includes many detailed suggestions for homes, schools, and other interior spaces. The strongest general recommendation is to bring in as much outdoor air as possible. Unfortunately for a large number of Americans, outdoor air brings along the stench of factories or slaughterhouses, and of course the smoke from fires raging in some states. Ejecting air is important too, and many houses and apartments already have exhaust fans in their bathrooms and kitchens, which it might be wise to employ when company comes over.
“If it gets too cold or hot, adjust the thermostat” is a guideline totally out of touch with reality for a lot of people. Staying warm in winter or cool in summer is a major issue for many Americans who can’t afford even another $5 on their utility bills. But for institutions, especially those with COVID-associated government money to help them out, the physical plant’s HVAC system is definitely the wisest place to spend it, if we want COVID-19 to ever go away.
Much safer air could be achieved in schools with portable HEPA Filter Systems. Dr. Richard Corsi talks about the necessary parts and ongoing requirements, if America decides to take on the job of retrofitting every classroom with certain equipment. It could be done for less than $10 per student per year, with recurring costs (for replacement filters) of about $3 per student per year. That is a pretty good deal, and who wants to admit that a child’s life is not worth an annual $13? At any rate, Dr. Corsi explains,
That leads to a 60% reduction in inhalation dose of aerosol particles. Capacity exists. It can be done now.
Then, if everybody is properly masked, there is another huge advantage. He explains additional steps that can add layer after layer of protection. One of those is a DIY filtering machine that can be made by a teacher and a team of students. Another incredibly enlightening Twitter thread that covers many topics within this large and confusing landscape was posted by Dr. Eric Feigl-Ding.
Science and technology journalist Chris Baraniuk wrote a guide to choosing a home air purifier:
If viruses are what you want to remove from the air, ventilation experts generally recommend you get an air purifier or cleaner with a high-efficiency particulate air (HEPA) filter. These thick, spongy filters contain a mass of fibers that trap airborne material. They cover a wide range of particle sizes and are 99.7% efficient at snaring matter that is 0.3 microns in diameter.
Once you’ve chosen a model, you then have to decide where to place it in a room. You should pick as central a position as possible — don’t stick it in a corner… [T]he space around the device should be free of obstacles, so avoid placing it under a desk, for example.
And for heaven’s sake, read the specs, or the manual, or watch an instructional video, or something.
Your responses and feedback are welcome!
Source: “How to use CDC building recommendations in your setting,” CDC.gov, 02/26/21
Source: Dr. Richard Corsi on Twitter, 02/18/21
Source: “Should You Buy an Air Purifier for Covid-19?,” Medium.com. 12/02/20
Image by Mike Licht/CC BY 2.0