Can face masks that help protect against COVID-19 also keep you safe from wildfire smoke?

As COVID-19 cases and hospitalizations continue to rise in several states throughout the country, some Americans are facing an additional challenge: smoke from wildfires that are raging across the West Coast.

Over the past few weeks, wildfires have destroyed parts of California, Oregon and Washington, setting more than 5 million acres ablaze, forcing thousands to evacuate their homes and causing poor air quality as far as the East Coast, according to the Red Cross. Public health officials have advised people to stay indoors, although doing so hasn’t stopped smoke from drifting inside some homes and causing respiratory problems.

Can face masks that help protect against COVID-19 also keep you safe from wildfire smoke? (Photo: Allen J. Schaben/Los Angeles Times via Getty Images)
Can face masks that help protect against COVID-19 also keep you safe from wildfire smoke? (Photo: Allen J. Schaben/Los Angeles Times via Getty Images)

Many states have implemented mask requirements to prevent the spread of COVID-19. But can those same face masks also help protect people from wildfire smoke? It depends on the type of mask.

“We’re battling two pandemics at the moment — one being a viral pandemic and the other one being the wildfires over on the West Coast,” Dr. Panagis Galiatsatos, an assistant professor in the division of pulmonary and critical care medicine at the Johns Hopkins School of Medicine, tells Yahoo Life. “We definitely want to limit people’s exposure to both.”

With COVID-19, masks help with what’s called “source control,” slowing the spread of the virus. According to the Centers for Disease Control and Prevention’s mask guidelines: “Masks are recommended as a simple barrier to help prevent respiratory droplets from traveling into the air and onto other people when the person wearing the mask coughs or sneezes.”

However, in the CDC’s guidelines on public health strategies to deal with wildfire smoke during the pandemic, the agency does not recommend relying on cloth masks with filters inserted or sewn into them to protect against wildfire smoke exposure “because the level of protection that they provide against [wildfire] particulate air pollutants is highly dependent on the fit of the mask and the characteristics of the filter.”

According to the Environmental Protection Agency, particles from smoke are typically very small — “particulate matter in wood smoke” has a size range of 0.4 to 0.7 microns in diameter. “For purposes of comparison, a human hair is about 60 micrometers [microns] in diameter,” says the agency. The EPA says that “such small particles can be inhaled into the deepest recesses of the lung and are thought to represent a greater health concern than larger particles.”

While the coronavirus itself is about 0.12 microns in diameter, according to the Mayo Clinic, Dr. Jonathan Parsons, a pulmonologist at the Ohio State University Wexner Medical Center, explains to Yahoo Life that the respiratory droplets expelled when someone coughs, sneezes or talks that “contain the viral particles are typically 5 microns [in diameter] — it’s not just the virus itself” being expelled.

“The particles that cause problems to the lungs and airway with smoke are much too small to be filtered by a cloth mask or surgical mask,” says Parsons. “But on the other hand, they are effective in terms of hindering the spread of COVID because the droplets are much larger relative to the particles that cause problems in smoke.”

For people who must be outside during the wildfires, the EPA recommends wearing a fitted N95 mask or P100 respirator (ones that are typically worn for automotive spray-painting or in construction), which can help reduce exposure to particles in wildfire smoke.

N95 masks — which also reduce the spread of the coronavirus and are commonly used in health care settings — are “engineered to filter out 95 percent of the particles that are 0.3 microns or larger,” explains Parsons.

If you’re planning on purchasing a respirator to reduce wildfire smoke exposure, the EPA recommends getting a “particulate respirator” that has been tested and approved by the National Institute for Occupational Safety and Health (NIOSH). The respirator should have the word “NIOSH,” as well as either “N95” or “P100,” on it. Also, the agency recommends choosing a respirator that has two straps that go around your head (not looped around the ears or one with a single strap) for a more secure fit.

According to the CDC, “other than N95 respirators, masks that are used to slow the spread of COVID-19 offer little protection against the harmful air pollutants in wildfire smoke.”

But Galiatsatos says that if there’s smoke in the air from wildfires, the best thing you can do is stay indoors. It’s also “the best way to not be exposed to the virus,” he adds.

“If you’re in an area where there’s wildfire, there really isn’t any safe way to be outside for an extended period of time,” says Parsons, who explains that the risk is the concentration of smoke particles in the air combined with the length of exposure to those particles. “The concentrations are so high right now that even short exposure” outside isn’t safe, he says.

For the latest coronavirus news and updates, follow along at According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.

Read more from Yahoo Life:

Want lifestyle and wellness news delivered to your inbox? Sign up here for Yahoo Life’s newsletter.