Buzz
While indoor plumbing is one of the major achievements of modern society, it still comes with a few drawbacks. Pipes can get blocked, water heaters can malfunction, and toilets can spray bacteria-laden poop clouds when flushed.
This latter point is why it’s advised to close the toilet lid before flushing. Researchers at the University of Colorado Boulder have now shown exactly what kinds of aerosolized feces are released.
As reported by Smithsonian, the team came up with the idea of using green lasers on a toilet, dimming the surroundings, and using cameras to capture the particles ejected during the flush, which scattered the laser light. Their study, published in the journal Scientific Reports, is titled “Commercial toilets emit energetic and rapidly spreading aerosol plumes,” which hints at the results.
As shown in the video above, it’s quite a spectacle. Particles were ejected nearly 5 feet into the air and some lingered for up to a minute. Others landed on the walls surrounding the toilet.
“We anticipated these aerosol particles would simply drift upward, but they shot out like a rocket,” said John Crimaldi, lead author and professor of civil, environmental, and architectural engineering, speaking with CU Boulder Today.
Toilets, as repositories of human waste, host a range of harmful bacteria and viruses, such as E. coli. A lidless toilet releasing these into the air presents a theoretical risk of inhaling these germs—not just from the current user, but from the many others who’ve used the toilet before.
For the experiment, researchers used only clean tap water, not actual feces, which may have impacted the particles’ speed or trajectory. (“The presence of fecal matter and toilet paper could alter plume dynamics in unpredictable ways,” the paper warns, which sounds concerning.)
They didn’t explore how particles might behave on a closed-lid toilet with only a small gap around the edges. But the general conclusion is clear: Public restrooms are nastier than we thought, and when using your own toilet, be sure to close the lid.
