Even when school is closed, air quality is important to maintaining a healthy indoor environment. Now that we are implementing reopening strategies, it’s imperative that we do all we can to protect students, teachers, and staff—and the families they will be going home to. While social distancing and face masks are still the most important protective measures against the spread of COVID-19 in schools, ventilation systems offer opportunities for prevention as well. The CDC and other advisory groups recommend that we “Improve central air filtration [...]