Checking out the classroom that I will teach in this semester at @UNCHussman. Normal capacity: about 90. COVID-19 capacity: 20.pic.twitter.com/fG71ou20tu
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That window looks like it can open! right now you can get two Blueair 211s for $459. These will do 5 air changes an hour in 1,000 square feet or so. https://www.blueair.com/us/air-purifiers/blue-pure-211-plus-twin-pack/1856.html … I have the 121+ at home and it's not super loud.
Every expert I spoke with recommends the usual HEPA filters. A regular HEPA filter is both less expensive and actually what you need.
Your article on ventilation was

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