People are being warned not to remove face masks when in public restrooms and enclosed spaces such as elevators after a study found people can easily contract the new coronavirus from using these facilities.
The study, conducted by a team of researchers led by Chulabhorn Research Institute researcher Kwanrawee Sirikanchana, found that using public toilets may increase the risk of Covid-19 through airborne transmission.
The study, published in the Water and Health Journalfocused on the effects of face masks and ventilation and the risk of respiratory transmission of Covid-19 in public toilets.
He looked at scenarios in which an individual used a public toilet after someone infected with Covid-19. One involved neither of them wearing face masks and others where they both wore N95 or surgical masks.
The study found that without a face mask there was a 10% risk of becoming infected, but the risk increased to almost 100% if the person infected with Covid-19 coughed or sneezed in the toilet. However, if both wore face masks, the risk was only 0.01%. According to the study, a 10-minute wait time might also reduce the risk of getting infected, but face masks offered the best protection.
Thammanitchpol Denpetkul, a senior lecturer at Mahidol University’s Faculty of Tropical Medicine, said the virus can be transmitted via droplets as small as PM2.5 dust particles.
He said respirators such as N95, KN95, KF94 and FFP2 offer the most effective protection when using public restrooms, while surgical masks are the next best option.
“Some cloth masks may not be good enough to protect against the virus…but if someone uses an N95 mask and wears it correctly, the risk is one in 100,000,” he said.