Could Flushing Send Out a Coronavirus-Filled ‘Toilet Plume’?

Surely you do not want to contaminate your beautiful baby-blue bathroom with a toilet plume? Photo: Getty Images

I know there is, and has been, a lot of information coming at you on a minute-by-minute basis, much of which feels fluid, and a brain can only absorb so much before it simply dissolves in the deluge. But if you remember just one more thing today, I nominate this gentle reminder: Please, close the lid before you flush the toilet. Just generally, but especially amid an ongoing pandemic wherein the enemy contagion may live in feces, and seems mainly to spread via droplets floating through the air. One uncovered flush could potentially burp a large cloud of aerosolized poop particles into your bathroom sanctuary, which is gross in any context, and certainly undesirable in our current COVID climate.

To be clear, the available evidence suggests that the coronavirus — although it has been found in human waste — is primarily transmissible person to person, through the teeny drops of spittle we spray as we speak, and scream, and sneeze, and so on. Still, a new study by researchers in China, published Tuesday in Physics of Fluids, urges caution when flushing public and private toilets, lest you release a fine geyser of fecal mist into the environment.

Researchers simulated viral spread via flushing in two types of toilets: annular-inlet toilets, whose bowls fill as water pours in all around the rim, and single-inlet toilets, which fill through a single spillway. In both types of toilet, but particularly in annular toilets, flushing created interior turbulence strong enough to send poop particles rocketing up and out. Apparently, 40 to 60 percent of those particles reached past the bowl’s brim, potentially “leading to large-scale virus spread,” the study says. This “toilet plume” spray radius extended as high as three feet off the ground, continuing to float there for over a minute.

“Flushing will lift the virus up from the toilet bowl,” co-author Ji-Xiang Wang of Yangzhou University warned the Washington Post. Where possible, Wang said, we “need to close the lid first and then trigger the flushing process.” And of course, thoroughly wash your hands, but you knew that.

Again, we lack the evidence to demonstrate that the coronavirus has been spreading this way; the point is that it could, and we’re mitigating risk. Unparalleled fun, we love it. Plus, the toilet plume has flown under our collective disgust radar for too long. “The aerosols generated by toilets are something that we’ve kind of known about for a while, but many people have taken for granted,” Joshua L. Santarpia, a University of Nebraska Medical Center professor of pathology and microbiology (who was not involved in the research), told the New York Times. “This study adds a lot of the evidence that everyone needs in order to take better action.”

And what is that better action? Close the lid. The lid has but one job, after all; let it do its thing.

Could Flushing Send Out a Coronavirus-Filled ‘Toilet Plume’?