The issue of restroom use is one that some people may be thinking about in the coronavirus era. I was reading this interesting paper the other evening – “Can a toilet promote virus transmission? From a fluid dynamics perspective” – from the journal Physics of Fluids. This assesses that if someone if infected with the virus, when the toilet is flushed and the lid is not placed down, then between 1,000 to 10,000 particles are ejected, with an average range of 1.5 metres. The particles are not all viral and will include some enteric bacteria.
The height at which particles are ejected is of importance, with the typical vertical rise of 1600 millimetres (mm). This is important, as the average height of mouths of a typical person is around 1600 mm, which is critical to the fecal–oral transmission. The data sowed that the highest level a particle can reach 27.4 centimetres at a time of 35 seconds. Moreover, the data showed that an average of 2,700 particles are propelled out of the toilet during a one-shot single-inlet flushing at a time of 70 seconds.
The risks are considerably lowered when the lid of a toilet is closed. The extent of the risk can be further illustrated in the case of a bacterial infection. For example, one study looing at legionella found that the chance of infection from public washrooms where the lid was up was on in 100,000. This risk was higher when the temperature was above 20 degrees Celsius. When the lid is on, there is a 99 percent reduction in contamination.
Further with public restrooms, some people might think to toilet seats in paper in a bid to prevent unwanted germs from getting on their bottoms. However, this is not a good idea since toilet paper generally contains more bacteria than toilet seats:. Toilet seats have a smooth, plastic surface which is specially-designed to prevent bacteria from surviving more than an hour. In contrast, toilet paper can have bacteria on it that lasts for days. If someone is concerned, it is best to use a disinfectant wipe to sanitize the seat prior to use.
In terms of risk in the time of the coronavirus pandemic, coronaviruses have been found to bind to porcelain, so they remain across several lavatorial uses and can potentially be ejected. Furthermore, the SARS-CoV-2 virus can remain viable for up to three days on this type of surface. As a way of protection, the application with bleach is recommended for public conveniences, such as every six hours.
