David Coil has been coordinating a project to do air filter testing for Sars-CoV-2 in Davis, CA schools in collaboration with Heather Bischel, Karen Shapiro, Roque G Guerrero, Randi Pechacek, and others. This has been supported by the Healthy Davis Together project.
Recently there have been a few news stories about this work and I thought I would post some links here.
Woodland Daily Democrat: Davis Joint Unified School District prepares against COVID-19 with air filters
Also see UC Davis Live on this topic: https://www.ucdavis.edu/news/media-advisory-uc-davis-live-back-to-school-safely
And see the Healthy Davis Together page on this: https://healthydavistogether.org/airfiltertesting/