It’s not something people like to talk about, but there’s a potential important source of covid-19 spread that deserves some attention: toilets.

Studies are showing that the novel coronavirus can be detected in stool samples and anal swab samples for weeks. In fact, scientists are testing wastewater as an early tracking system for outbreaks. And a recent case on an airplane identified the airplane bathroom as the potential source.

Here’s what we know: When you flush a toilet, the churning and bubbling of water aerosolizes fecal matter. That creates particles that will float in the air, which we will now politely call “bioaerosols” for the rest of this article.