Skip to content
Asking Never Hurts

Wildfires Provide Another Reason to Mask Up

A young man skateboards in front of the boardwalk in Santa Cruz, California, on Thursday. Smoke from the CZU August Lightning Complex fires have filled area skies for several days. (Anna Maria Barry-Jester/KHN)

If you have declined to wear a face mask during the COVID-19 crisis, you might want to reconsider, as the smoke from over 300 wildfires chokes people across central and Northern California.

But you are going to have to think a little more about what kind of mask is best.

The fires have spewed toxic substances far and wide, raining ash across the region and leaving an acrid brownish-gray haze. Air quality in much of the Bay Area was the worst in the world for a few days last week. And fire season is only just beginning.

The biggest health risk: tiny particles, less than 2.5 microns in diameter, that make up 80% of wildfire smoke. They can enter the bloodstream through the lungs, damaging the airways and the heart. The risks are greatest for the old and very young, and those with preexisting heart and lung conditions.

The best defense against the smoke is simply to stay inside. “If you don’t have to go out, don’t go out,” says Dr. Mary Prunicki, director of air pollution and health research at Stanford University’s Sean N. Parker Center for Asthma and Allergy Research. She advises keeping doors and windows shut and using an air purification device to filter out the smoke particles.

And refrain from strenuous exercise. “You have permission to be a couch potato,” says Anthony Wexler, director of the Air Quality Research Center at the University of California-Davis.

If you must be outside for any extended period, you should cover your face — and that’s where the convergence of COVID-19 and wildfires poses challenges, though not insurmountable ones.

The relatively loose-fitting cloth face coverings and blue surgical-style masks that many of us wear in public to prevent spreading the coronavirus are not particularly useful against smoke, though they can provide some protection, research has shown. Cloth masks reduced airborne particles by 57%, according to one study. Another study showed that surgical and homemade masks reduced particle concentrations fourfold and threefold, respectively.

That compares with a hundredfold reduction by N95 filtering facepiece respirators, commonly known as N95s. The number 95 signifies that they filter out 95% of particles.

“The N95s are great, if you can get your hands on one,” says Wexler.

And therein lies the rub. Huge demand for N95 masks among health care workers on the front lines of COVID-19 led to supply constraints in the spring that continue this summer.

“We are extremely concerned about the availability of N95 masks,” says Gail Blanchard-Saiger, vice president of labor and employment at the California Hospital Association. Administrators at one hospital recently told her they had not received a single shipment of N95s since March. Another said their hospital had 350,000 N95s on back order and were lucky to get 200 a month.

I conducted a (very unscientific) survey of my own, calling four hardware stores and five medical supply stores in Southern California, where I live, to ask if they carried N95s. None of the hardware stores and only two of the medical supply stores did.

If you do get hold of some N95s, be aware that they work properly only with a tight fit against your skin, providing a seal that minimizes leakage. They will likely be too big for children, and if you have facial hair it will interfere with the fit.

The tight fit of a properly functioning N95 means it is uncomfortable, “so you’re not going to wear it a really long time, because it’s going to be really annoying,” Wexler says.

If you have a chronic respiratory condition such as asthma or COPD, check with your doctor before wearing a mask.

Gina Spadafori, a West Sacramento resident who’s had asthma all her life, bought a box of N95s during the Camp Fire in late 2018 and had one left this month when her neighborhood was engulfed by smoke from a multitude of wildfires burning in the region.

She put it on before she went out to check on her goats and chickens one recent morning. “I still immediately got tightness in my chest and some problems breathing,” says Spadafori, 62. “So I can imagine that going out to the barn without it would have been a pretty bad mistake.”

Given the importance of conserving masks during the pandemic, it’s OK to reuse N95s, says Dr. Nicholas Kenyon, division chief of pulmonary, critical care, and sleep medicine at UC Davis Health. “If they are not soiled and wet, and they are still intact, you can use them for several days, hopefully to get through this.”

If you can’t get hold of N95s, don’t fret. You have other options. One is a kind of alternative N95, known as the KN95, which is abundantly available. Eight of the nine stores I called had them in stock.

The KN95s, produced mainly by Chinese manufacturers, are meant to filter out 95% of airborne particles, like the N95s. But beware: They do not always perform as advertised. The Food and Drug Administration rescinded its emergency authorization for some KN95 brands after a study this year found they did not meet the 95% target.

The Centers for Disease Control and Prevention website provides filtration efficiency reports on a large number of N95 and KN95 respirators.

You might also consider insertable PM2.5 filters, designed to fit inside cloth or surgical masks. You can buy them online; they are abundant and inexpensive. The downside is that it may be difficult to get a tight fit, so there could be leakage.

They are “not as good as the real thing, but way better than nothing,” says Wexler.

If you want to go Darth Vader, and a bit more upscale, check out elastomeric respirators — tight-fitting rubber or silicone masks that come with filtration cartridges and offer protection at least equivalent to an N95 and, in some cases, better.

They also have exhalation valves, which makes it easier to breathe. But here’s the problem with that: You expel respiratory droplets. Great for coping with smoke, but potentially risky for those you encounter in the midst of a pandemic. Like the N95s, their tight fit can make them hard to wear for long periods of time — especially in high heat.

Whatever you decide, one thing seems inescapable: With a society rendered germophobic by the pandemic and with wildfires an ever-increasing threat, masks are fast becoming an indispensable part of our wardrobe.

“I think this is the new normal for the 21st century,” says Dr. Richard Jackson, a professor emeritus at UCLA’s Fielding School of Public Health and former head of California’s Department of Public Health under Gov. Arnold Schwarzenegger. “You keep flashlight batteries in your house, and you keep good quality masks.”

This story was produced by KFF Health News, which publishes California Healthline, an editorially independent service of the California Health Care Foundation.

Related Topics

Asking Never Hurts California COVID-19 Public Health States