Using A Public Restroom? Mask Up!

Using A Public Restroom? Mask Up!:

 Think you don’t need to worry about COVID-19 while using a public restroom? Researchers from Yangzhou University in China recently reported that flushing publ

Newswise — WASHINGTON, August 18, 2020 -- Think you don’t need to worry about COVID-19 while using a public restroom? A group of researchers from Yangzhou University in China recently reported that flushing public restroom toilets can release clouds of virus-laden aerosols for you to potentially inhale.

If that’s not cringeworthy enough, after running additional computer simulations, they’ve concluded that flushing urinals does likewise. In Physics of Fluids, from AIP Publishing, the group shares its work simulating and tracking virus-laden particle movements when urinals are flushed.

The researchers’ work clearly shows public restrooms can be dangerous places for potentially becoming infected from a virus, especially during the COVID-19 pandemic. Other work has shown that both feces- and urine-based virus transmission is possible.

“To do this, we used a method of computational fluid dynamics to model the particle movement that occurs with the act of flushing,” said Xiangdong Liu. “The specific models are the volume of fluids model and discrete phase model.”

Flushing a urinal, much like flushing a toilet, involves an interaction between gas and liquid interfaces. The result of the flushing causes a large spread of aerosol particles to be released from the urinal, which the researchers simulated and tracked.

What the simulations revealed is disturbing. The trajectory of the tiny particles ejected by flushing a urinal “manifests an external spread type, with more than 57% of the particles traveling away from the urinal,” said Liu.

But that’s not all. When men use urinals within a public restroom, these tiny particles can reach their thigh within 5.5 seconds when compared to the toilet flush, which takes 35 seconds to reach slightly higher. Particles from urinals, however, “show a more violent climbing tendency,” Liu said. “The climbing speed is much faster than toilet flushing.”

Urinals are used more frequently within densely populated areas, and the researchers point out that particles will travel faster and farther, which poses a serious public health challenge.
This work underscores how important it is to wear a mask within public places but especially restrooms.

“From our work, it can be inferred that urinal flushing indeed promotes the spread of bacteria and viruses,” says Liu. “Wearing a mask should be mandatory within public restrooms during the pandemic, and anti-diffusion improvements are urgently needed to prevent the spread of COVID-19.”
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Study reveals COVID-19 transmission rate on trains

Study reveals COVID-19 transmission rate on trains:


Newswise — A study by scientists from the University of Southampton has examined the chances of catching COVID-19 in a train carriage carrying an infectious person.
Based on high-speed routes in China, researchers from WorldPop found that for train passengers sitting within three rows (widthwise) and five columns (lengthwise) of an infected person (index patient) between zero and ten percent (10.3) caught the disease. The average rate of transmission for these 'close contact' travellers was 0.32 percent.

The study, in collaboration with the Chinese Academy of Sciences, China Academy of Electronics and Information Technology, and Chinese Centre for Disease Control and Prevention, also showed that passengers travelling in seats directly adjacent to an index patient suffered the highest level of transmission, with an average of 3.5 percent contracting the disease. For those sitting on the same row, the figure was 1.5 percent.

The 'attack rate' for each seat - the number of passengers in a given seat diagnosed with COVID-19, divided by the total number of passengers travelling in the same seat - increased by 0.15 percent for every hour that a person travelled with an index patient. For those in adjacent seats, this rate of increase was higher at 1.3 percent per hour.

Interestingly, the researchers found that only 0.075 percent of people who used a seat previously occupied by an index patient went on to contract the disease.
Details are published in the journal Clinical Infectious Diseases.
The WorldPop team, experts in population mapping, used sophisticated modelling to analyse anonymised itinerary and infection data relating to train passengers on China's high-speed G train network. This included those who had COVID-19 at the time of travel and their close contacts (who showed symptoms within 14 days of travel). The data, covering a period between 19 December 2019 and 6 March 2020, included 2,334 index patients and 72,093 close contacts. Their travel times ranged from between less than an hour to eight hours.

Lead investigator, Dr Shengjie Lai, comments: "Our study shows that although there is an increased risk of COVID-19 transmission on trains, a person's seat location and travel time in relation to an infectious person can make a big difference as to whether it is passed on. The findings suggest that during the COVID-19 epidemic it is important to reduce the density of passengers and promote personal hygiene measures, the use of face coverings and possibly carry-out temperature checks before boarding."

The researchers conclude that given the attack rates estimated for passengers in the same row as an index patient, a safe social distance of more than one metre is required for one hour spent travelling together. After two hours of contact, they consider a distance of less than 2.5 metres may be insufficient to prevent transmission.

Director of WorldPop, Professor Andy Tatem adds: "Our research is the first to quantify the individual risk of COVID-19 transmission on public transport based on data from epidemiological investigations of disease cases and their close contacts on high-speed trains.

"It shows that the transmission risk not only relates to the distance from an infected person, but also the time in their presence. We hope it can help to inform authorities globally about measures needed to guard against the virus and in-turn help to reduce its spread."

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