Wearing cloth masks does not prevent dust

Masks can block 65% of large particles, but they cannot protect the wearer from particles smaller than 2.5 micrometers.

People in Beijing, China, wear masks to protect against air pollution. Photo: Stephen Shaver.

According to UPI, face masks are a common item in many Asian cities where people have to deal with severe air pollution. However, according to a research team at the University of Massachusetts Amherst, the most common types of masks have limited protection against harmful dust.

The team’s tests showed that the most expensive cloth masks blocked 65% of large particles, but they did not protect the wearer from particles smaller than 2.5 micrometers. Cheap masks popular in Nepal, China, India and many Southeast Asian countries offered little protection.

"Masks help us reduce our exposure to airborne dust to a certain extent. But commonly used cloth masks have poor protective performance," the study authors concluded in a paper published on August 18 in the journal Exposure Science and Environmental Epidemiology.

Richard Peltier, lead author of the study, said masks give people a false sense of security, giving them confidence when going to places with severe pollution.

“Millions of people wear masks and they feel safer. But the mask doesn’t protect them from the exhaust from the diesel truck right next to them,” Peltier said.