Face masks should be washed and tumble dried each day, study finds

Sarah Knapton
·2-min read
Masks prevent emissions but also store droplets and aerosols and could be a source of infection - Getty Images Europe
Masks prevent emissions but also store droplets and aerosols and could be a source of infection - Getty Images Europe
Coronavirus Article Bar with counter
Coronavirus Article Bar with counter

Face masks should be washed daily at 60C and tumble dried if possible in order to completely kill off any traces of coronavirus, experts have said.

A recent study by the University of California found that particles can build up in masks and regular washing is important.

Professor William Ristenpart, a chemical engineer at the university, found that while masks prevent emissions they also store droplets and aerosols and could be a source of infection. 

"Our results suggest that individuals using homemade fabric masks should take care to wash or otherwise sterilise them on a regular basis to minimise the possibility of emission," he wrote in a recent paper published in Nature. 

The World Health Organisation (WHO) recommends that reusable masks should be changed more frequently than daily if they get dirty, damp or wet. They should also be stored in a clear, resealable plastic bag between uses and only touched by their elastic straps. 

Previous research has shown that bacteria and viruses can linger on the outside of masks. The Government recommends that people should avoid touching the part of the covering that has been in contact with the nose or mouth, and should wash their hands after touching a mask. 

Face coverings should also not be placed on a table when eating in a restaurant or drinking in a pub

Experts at Johns Hopkins University in the US recommend keeping at least two reusable masks so that one can be in the wash. If washed by hand, masks should be scrubbed for at least 20 seconds and then dried on a high heat in a tumble dryer.

The University of New South Wales, in Sydney, said it was important to wash masks after each wearing after finding virus on the inside and outside of both surgical and cloth masks.

Studies have demonstrated that surgical masks can contain and therefore reduce the dissemination of droplets and aerosols produced by a sick wearer by up to three to four-fold, and home-made cloth masks up to  two to four-fold.

Surgical masks can also protect the wearer to some degree by reducing the exposure to incoming droplets and aerosols by up to six-fold.