Bay Area officials advise residents against using N95 masks for wildfire smoke

The N95 masks feature particulate respirators, are designed to filter at least 95 percent of airborne particles and are approved by the National Institute for Occupational Safety and Health. But an official from the San Francisco Health Department warned as wildfire season approaches that residents should look for alternatives. less The N95 masks feature particulate respirators, are designed to filter at least 95 percent of airborne particles and are approved by the National Institute for Occupational Safety and Health. But an official ... more Photo: Lea Suzuki / The Chronicle Buy photo Photo: Lea Suzuki / The Chronicle Image 1 of / 35 Caption Close Bay Area officials advise residents against using N95 masks for wildfire smoke 1 / 35 Back to Gallery

Many Bay Area residents have a stash of N95 masks in their homes.

People widely purchased these in recent years when smoke from record-breaking wildfires enveloped Northern California. Stores sold out of the masks during the 2018 Camp Fire when San Francisco saw some of its worst-ever air-quality days.

The N95 masks feature particulate respirators, are designed to filter at least 95 percent of airborne particles and are approved by the National Institute for Occupational Safety and Health.

But in a recent conversation with The Chronicle, an official from the San Francisco Health Department warned as wildfire season approaches that residents should look for alternatives.

"Masks may not be the answer for a lot of people," said Dr. Jan Gurley, director of public health emergency preparedness and response with the San Francisco Department of Public Health. "We reach for them because they're easy, and sometimes they make you feel a little better. But there are no substitutes for getting to where the air is clean."

The best places for clean air are buildings with sealed windows and HVAC systems, and ideally your home falls into this category. But if your windows are drafty and your home lacks an adequate ventilation system and air filter, you may need to look elsewhere. Indoor shopping malls are an option, and people can also turn to their city governments that have gotten into the habit of providing clean air spaces when air-quality is poor.

When smoke choked the Bay Area during the Camp Fire in 2018 and the North Bay fires in 2017, many cities opened libraries, community centers and other government buildings for the general public.

"People should call their cities now to find out where they will have clean air spaces in the next wildfire event," advised Lisa Fasano, communications director for the Bay Area Air Quality Management District (BAAQMD).

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While spending time inside might be best for the lungs, this isn't practical for everyone. People often have to step outside to walk to their car or to take public transit. Should you wear a mask?

"The advice is this: If it makes you feel better, wear one," says Francis Zamora, a spokesperson for the Department of Emergency Management. "If it makes you feel worse, take it off immediately."

The advice comes with one major caveat, and that is, if you chose to wear the mask, the likelihood of it doing more harm than good is high.

The masks were designed for worker safety, and workers go through a certification process that takes up to an hour to complete and determine whether a mask can properly seal on their face.

"There's a checklist, and if you hit any of those conditions where a mask isn't recommended, you shouldn't wear it," says Zamora. "For example, if you have facial hair, that's not going to work for you because the particulates the respirators are blocking are smaller than your facial hair. If there's a gap, those particulates are going to get through there."

When a mask is properly sealed, it's hot and uncomfortable to wear and breathing is strenuous. "They make the heart and lungs work harder and can cause respiratory distress for people with breathing conditions," says Fasano.

Because the masks can be smothering, people often take them on and off to reduce the stuffiness and heat. This allows particulate matter to enter the masks.

"We know people need to walk to transit, walk the dog, and get kids to school, but although it may be really smoky out, smoke is something that impacts people over long periods of time, not short durations and the potential health consequences of wearing a mask while exerting oneself far outweighs the potential harms of not wearing one," says Fasano.

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The Air Quality District and the Department of Emergency Management are part of an effort among local agencies to provide Bay Area residents with consistent guidance on how to protect themselves from wildfire smoke.

"We know we're going to have it again," Fasano said. "We're telling people to prepare now."

One way residents can get ready is by finding ways to improve the air quality in their own homes, including sealing doors and windows, and purchasing a non-ozone HEPA air purifier to be used in the room where you spend your most time, likely the bedroom.

Zamora adds that you can also purchase a MERV-13 filter for your home's HVAC system to filter out particulates. "You don't want to run that thing all the time," he said. "Only during a smoke event."

In the past 20 years, 16 out of the 20 worst days for particulate matter have been in the past two years, and these pollution days are all the result of wildfires. "This is looking like the new normal," Fasano said.

For more information on how to prepare for poor air-quality days, the San Francisco Department of Emergency Management offers tips.

Amy Graff is a digital editor SFGATE. Email her at agraff@sfgate.com.