It’s called toilet plume. And yes, it’s exactly what it sounds like.
When you flush a toilet, the force of the water creates a spray of tiny aerosolized droplets — droplets that can carry bacteria and other microorganisms from whatever was just in the bowl. Research published on PubMed Central confirms that flush toilets produce substantial quantities of this aerosol, that the particles are small enough to carry bacteria, and that the tiniest droplets can evaporate into even smaller particles — called droplet nuclei — that are small enough to be inhaled deep into your lungs.
And they don’t just float lazily upward. A study highlighted by CU Boulder researchers found that these airborne particles shoot out at speeds of about 6.6 feet per second, reaching nearly 5 feet above the toilet bowl within just 8 seconds of flushing.
That’s fast. And that’s high.
Once those particles are in the air, they don’t just disappear. The research notes they can remain viable — meaning alive and potentially active — for extended periods, and they can travel with air currents around the bathroom.
So what does that mean practically? Your toothbrush sitting on the counter near an open toilet? Your hand towel? Your phone you set on the edge of the sink? All of them are in the splash zone.
The fix is genuinely simple: close the lid before you flush. That’s it. It doesn’t eliminate the plume entirely, but it dramatically reduces how far and how high those particles travel.
Also worth knowing: bathrooms without lids — like a lot of public restrooms — are basically just doing this into open air every single flush. It’s one of the less glamorous realities of shared spaces.
None of this means you’re going to get sick every time you use a bathroom. Your immune system handles a lot. But it’s a good reason to keep your toothbrush in a cabinet, wash your hands thoroughly after using the toilet, and just… close the lid. Small habit, genuinely useful.