America needs to broaden its pandemic-fighting tactics — particularly regarding indoor air quality. Better ventilation and filtration inside buildings could do a great deal to slow the spread of coronavirus, as well as reduce illness and death of all kinds in the future.

Since the pandemic started, it’s become a cliché that it’s very hard to catch COVID-19 outdoors. Where an aerosol virus can float and travel long distances or hang in the air for hours inside, outside it generally dissipates rapidly.

It’s not that hard to make an indoor space similar to outdoors in this respect. You just need some combination of ventilation — that is, regularly replacing the indoor air with outdoor air — and filtration. Airlines are an excellent proof of concept. One would think that sitting in a tin can for hours with people packed in like sardines would be a huge infection risk, but airlines have rapid air purification systems that both continually introduce new fresh air and filter it through hospital-grade HEPA filters. Sure enough, despite hundreds of millions of people having flown over the past 20 months, there are only a few dozen confirmed cases of coronavirus transmission on airlines.