FACT CHECK: Are masks with valves less effective at preventing the spread of COVID-19?
TRUE. Masks with valves are not as effective at preventing the spread of COVID-19 compared to a plain cloth or surgical mask.
Since the COVID-19 lockdown began in March, a huge number of private companies have begun selling face masks. Some of them have been selling masks with an exhalation valve on the front, including Mississauga-based Plus Guardian, Walmart and numerous Amazon vendors. Plastic valves at the front of the mask make them more breathable and comfortable to wear, but they are actually less effective at reducing the spread of COVID-19 than other masks, including regular cloth and surgical masks.
In fact, valve masks are no longer authorized for air travel in Canada “as they don’t protect against droplets,” according to the Canadian federal government’s website. Health Canada and the US Centers for Disease Control and Prevention have recommended against using masks with valves, as have health authorities in the European Union and African Union.
Cloth and surgical masks—the sort recommended for everyday use by the public—are intended to protect other people in case you are infected with COVID-19. Exhalation valves do the opposite, as they are designed to filter the air you breathe in but not the air you breathe out.
A study at Florida Atlantic University found that an exhalation valve on an N95 mask “significantly reduces the effectiveness of the mask as a means of source control, as a large number of droplets are able to pass through the valve unfiltered.” The scientists conducting the study wrote that they expect the findings to apply to cloth and surgical masks with valves as well. (Some companies, like Plus Guardian, claim their masks have layers of fabric between the exhale valve that filter the air, but all valve masks have been banned for air travel nonetheless.)
Regular surgical masks performed much better in the study, although there was a difference between the brands that the researchers tested. Cloth or surgical masks won’t protect you from COVID-19 entirely on their own, but experimental studies and population data show that they do appear to reduce the spread of the virus.
Overall, public health authorities and medical researchers do not consider masks with valves to be a reliable way to prevent the spread of COVID-19. To be safe, it’s better to use a plain cloth or disposable mask with at least two layers of material.
Image via AIP Publishing.