3M brand N95 particulate respirators are displayed on a table on July 28, 2020 in San Anselmo, California.
 (Justin Sullivan/Getty Images)

Masks for Smoke and COVID-19 — What Kind Is Best?

Masks for Smoke and COVID-19 — What Kind Is Best?

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Updated May 13, 2021

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Californians have become familiar with masks in recent years.

First we learned about the power of N95 and N100 masks to protect ourselves from wildfire smoke. During the pandemic, masks of all kinds became a part of our daily wardrobe.

As this year's fire season approaches, the pandemic continues, and our relationship to masks evolves as more and more Americans get vaccinated, just what should we cover our nose and mouth with if wildfire smoke and the pandemic collide again?

Here's our best advice, for now.

Cartoonist Mark Fiore's Take

N95 Masks

"The best mask for protecting oneself from wildfire smoke is an N95. That's also the best mask for protecting oneself from coronavirus," UCSF pulmonologist and professor of medicine Dr. John Balmes said. Read more about how these masks work, and why they're so effective.

N95 masks are no longer in short supply either, as they were in the early part of the pandemic, so you don't need to worry about taking supplies of these masks away from health care providers.

Thursday, August 20, 2020 off Pleasant Valley Road in Vacaville. (Peter Arcuni/KQED)

But some public health officials say N95s aren't for everyone. Veronica Vien, a public information officer for the San Francisco Department of Public Health, said that they can be uncomfortable to wear for long periods of time and must "provide a tight seal around the wearer’s mouth and nose" to work effectively.

"If an N95 respirator makes you feel better, wear it. If you feel worse, please don't!" Vien said.

Balmes also said some types of KN95 masks, which are similar to N95 masks, but made in China, are also good.

N95 masks with exhalation valves work well for wildfire smoke, but are less effective at stopping the spread of disease — even with tape over the valve.

Surgical Masks

"They're actually somewhat protective with regard to wildfire smoke because they’re standardized," Balmes said. Balmes estimated surgical masks can reduce exposure to wildfire smoke by roughly 20%.

Cloth Masks

A cloth mask — which is primarily used to limit the spread of the virus — does not filter out wildfire smoke. As the CDC notes, cloth masks "do not catch small, harmful particles in smoke that can harm your health."

If you are masking up because you are inside and it is required, however, cloth masks can still slow the spread of coronavirus.


What Else Can I Do to Protect Myself?

While masks are a good option, public health officials say the most effective way to keep yourself safe from wildfire smoke is to stay inside.

Below is an interactive, crowdsourced air quality map from the private company PurpleAir. Read more information on air quality and how it's measured.

This advice may not feel particularly helpful or possible during a heat wave, or with impending evacuation orders. But officials with the state Office of Emergency Services still recommend that residents stay indoors with the doors and windows shut and with the air conditioning running if possible.

The California Air Resources Board also recommends mechanical air cleaners with a high efficiency particulate air (HEPA) filter that collects very small particles and does not emit harmful substances. These air cleaners can dramatically reduce indoor particle levels, in some cases by more than 90%. See a list of air cleaning devices here.

If you don't have air conditioning — which makes closing doors and windows especially difficult during a heat wave — consider getting some battery-operated fans and reducing activities that increase indoor air pollution, like burning candles, cooking on gas stoves or vacuuming.