Katharina Buczek
First, the engineers actually installed a working commercial toilet on top of a metal frame inside the fluid mechanics lab. This process was easier than lugging all of their equipment to the nearest bathroom since the installed porcelain throne could be perfectly aligned with their lasers.
Then, after calibrating their green lasers and finally flushing the toilet, the results defied their expectations.
“It’s like a volcano erupting. Some of us were stunned into silence. Some of us were just laughing out of disbelief, and also kind of like, ‘Oh my God, we are really on to something here,” Crimaldi explained.
Afterward, the team decided to train a pulsed laser and a few scientific cameras onto the spray in order to calculate the speed of each water particle.
And ultimately, they found that aerosols from this toilet plume can reach a max velocity of nearly 4.5 miles per hour.
Yes, once airborne, these microparticles do eventually settle down. However, even almost eight seconds after flushing the toilet, the researchers found that airborne particles still hover over five feet above the toilet bowl’s rim. For reference, this is well above nose level for most adults.
So now, with these gross findings, the engineers are starting to rethink their bathroom safety precautions.
“I certainly am much more inclined after seeing these videos to wear a mask in a public restroom than I might have been before,” Crimaldi admitted.
It is also crucial to reiterate that the study was conducted using toilets filled with clean water. But, once human fecal matter, urine, and toilet paper are added into the mix, Crimaldi suspects the microscopic flume might be even more chaotic.
“I have an intuitive sense that the presence of solids might exacerbate the problem because there are just additional things for the water to impinge on and to create more opportunities for this energetic mixing of fluids,” he explained.
So now, the researchers are hopeful that their study’s findings will serve as a launchpad for future research in the travel of pathogens and bacteria in aerosol clouds.
