Why simple cloth masks without valves are better at stopping the spread of COVID-19 – SF Gate

angela.fritz@washpost.com

Public health specialists have been suggesting mask-wearing to prevent respiratory droplets from spreading out into the air when you breathe out, speak, cough or sneeze, and the valves enable those droplets through.
Medical masks, youll observe, do not have valves.

The 3M company, that makes valve masks for such professions, shows on its website how they work: breathed in air is filtered through the material part of the mask, and hot, damp exhaled air heads out through the valve. The system may be what you want when tearing out a kitchen for renovation, however the valve beats the purpose when youre trying to slow the spread of a virus.

” Any mask that integrates a one-way valve (normally a raised plastic cylinder about the size of a quarter on the front or side of the mask) that is developed to assist in simple breathing out enables droplets to be released from the mask, putting others nearby at danger,” the order says.
The Centers for Disease Control and Prevention advises easy cloth masks for the public to avoid the spread of covid-19. A few layers of cotton prevent the majority of the potentially infectious respiratory droplets from leaving into the air around you, and they are also much cooler than the form-fitting N95 masks.