Public toilets create virus-filled 'clouds' and lids don't help much

Last summer, a study was published that found evidence flushing toilets could disperse SARS-CoV-2, the virus behind COVID-19, into small aerosol particles in the air. A new study from Florida Atlantic University builds upon that, reporting that installing lids on these public toilets may still be inadequate for protecting against this potential health hazard.

A number of studies have found evidence that a small percentage of the SARS-CoV-2 virus can survive through the gastrointestinal tract and remain detectable in stool/urine samples collected from patients. This is a problem when it comes to public restrooms, which typically have multiple aspects that increase the risk of spreading the virus: toilets without lids, high-pressure flushing, and potentially poor ventilation systems.

The researchers cite a number of other concerns related to public restrooms, including their typically crowded nature and the number of people that visit them. Using normal ventilation conditions, the researchers studied the small droplets that result when a urinal and toilet is flushed, finding that these public spots may 'serve as hotbeds for airborne disease transmission.'

SARS-CoV-2 is only one of the many viruses that could potentially be transmitted through aerosolized particles in bathrooms, joining others like norovirus. Though lids on toilets help reduce the aerosol 'clouds' caused by flushing, the study found that they're not enough on their own to offer protection from possible transmission.

The study's co-author Manhar Dhanak, Ph.D., explained:

The study suggests that incorporation of adequate ventilation in the design and operation of public spaces would help prevent aerosol accumulation in high occupancy areas such as public restrooms. The good news is that it may not always be necessary to overhaul the entire system, since most buildings are designed to certain codes. It might just be a matter of redirecting the airflow based on the restroom's layout.