Is the coronavirus “spread by aerosol particles which are small enough to go through every mask?”

Stock made this claim about 15 minutes into the school board meeting.

This is partly true, but needs context to prevent correct information from yielding a false conclusion. COVID-19 can be transmitted through larger droplets, or they can “dehydrate and linger as ‘droplet nuclei’ in the air where they behave like an aerosol,” according to the New England Journal of Medicine. The aerosols could still pass through a mask, but masks slow the spread of the coronavirus.

Dr. Payal Kohli at the University of Colorado Anschutz medical campus told VERIFY the claims Stock made were partly true.

“There’s two ways in which the virus spreads through the air. One is through large droplets, these are large droplets when we talk or laugh or sing, that small little bits of saliva come out, those usually tend to fall kind of closer to the ground. The other is the smaller aerosols,” Kohli said.

“Think of it like a suspended virus particle in the air, almost like smoke, and it just kind of floats around. So the simple cloth masks are actually quite effective at preventing droplet transmission, because they catch those droplets, number one, so they prevent you from emitting them out to somebody else. And then number two, they serve as a barrier of protection from somebody else receiving those droplets,” Kohli said.

“Now, just like with cigarette smoke, you could be wearing a mask and still smell the cigarette smoke because those aerosols, which can suspend in the air, can get through the simple surgical mask. But the N-95 respirators do offer superior protection against both aerosols as well as those droplets,” she continued.

Stock provided the Mt. Vernon school board with studies that, he said, support his contention that masks do not provide protection against the transmission of tiny COVID-19 particles. VERIFY reviewed those studies. While some do raise questions about the effectiveness of masks, others are inconclusive. One of the studies cited by Stock has been retracted by the medical journal that published it because the publisher determined the study “misquotes and selectively cites published papers.” After a broader review of scientific studies, the journal reported high quality masks worn properly do effectively reduce the transmission of COVID-19.

Other studies cited by the CDC came to the same conclusion: properly-worn masks are effective in slowing and significantly reducing the spread of coronavirus.