https://clarkvangilder.com/2020/08/04/blown-away/

https://clarkvangilder.com/2020/08/22/poor-ventilation-in-schools/

https://elemental.medium.com/air-purifiers-air-filters-and-the-best-diy-hacks-to-reduce-the-coronavirus-risk-14169e8839c5

https://www.wired.com/story/could-a-janky-jury-rigged-air-purifier-help-fight-covid-19/

https://www.youtube.com/watch?v=kH5APw_SLUU

Vangilder posts two wonderful discussions on the physics, capacities, efficacy, purchase choice, and placement of filters improving classroom ventilation and air filtering to make classrooms safer from coronavirus. Many others provide a number of clever hacks manufacturing room filters using 20-in square box fans and 20-in furnace MIRV13+/HEPA filters available from any hardware store (off-brand filters are cheaper). Simply taping a filter (4 in deep rather than 1 in) to the intake side of a fan (so suction helps hold it tight) is an adequate start. A more advanced idea is to assemble a cube 20-in long on a side with outward flowing 1-in filters held together/sealed with plastic packing tape, where one side of the cube is a 20-in box fan blowing room air into the cube. The cube has easier flow due to more surface area (as does the deeper filter) so less...

AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.