A person looks at the New York City skyline covered in smoke. Share on Pinterest
N95 face masks offer the best protection from lung damage from wildfire smoke, according to experts. Angela Weiss/AFP via Getty Images
  • Health experts say an N95 mask is your best bet for protecting yourself from wildfire smoke.
  • Research shows KN95 masks may protect your lungs just as effectively as N95 masks.
  • While surgical masks became popular during the COVID-19 pandemic, they are ineffective at protecting against wildfire smoke.

The 2023 wildfire season is underway, and severe wildfires in Canada have meant that smoke is impacting a large swath of the United States.

The Air Quality Index (AQI) recently became dangerously high in major cities like New York and Chicago, with some of the worst levels on record. For the duration of wildfire season, many U.S. states may continue to face unhealthy air quality levels for sensitive groups.

Exposure to smoky air has negative health consequences, such as:

  • asthma attacks
  • visits to the emergency room
  • increased inflammation

Well-made N95 and KN95 face masks, such as those worn during the COVID-19 pandemic, are your best bet against the harmful chemicals in wildfire smoke.

Here’s the lowdown on how N95 and K95 face masks can keep you safe from the hazardous particles in smoky air in wildfire smoke.

The N95 face mask offers the most protection against wildfire smoke.

If fitted and worn correctly, the N95 mask filters out 95% of particles larger than 0.3 microns, so they’re very efficient with keeping out the 2.5-micron particles in wildfire smoke, according to Dr. William Lang, the chief medical officer at WorldClinic and a former director of the White House Medical Unit.

“Infection generally requires that the virus is carried by some other particle, so respirators that… filter particulates do effectively reduce viral exposure,” Lang told Healthline, noting this is why the N95 mask effectively protects people against viral infections like COVID-19.

N100 or P100 filters keep out 99.97% of these same particles but can make breathing difficult, Lang added.

“N95 masks are the type of face covering protection that I would recommend for somebody who is outside during the air pollution caused by wildfires,” said Marina Vance, an assistant professor in the Department of Mechanical Engineering and in the environmental engineering program at the University of Colorado, Boulder, told Healthline.

If you have an N95 mask with a valve, Vance recommended putting something on top, like a cloth mask, or sealing it off to protect others around you.

Vance also recommended using the mask a few times, then tossing it. In some cases — like when the conditions are hazardous — it may be best to use it once and toss it. N95 masks are not meant to be reused; they become less effective with each use or cleaning.

“A lot of people are reusing their N95s and trying to disinfect them, and that will cause a reduction in efficiency,” Vance said. “If the mask is starting to develop cracks or looks wrinkly, it’s no good.

If you’re having a hard time getting an N95 mask, the good news is that KN95 masks can work just as well.

They’re very efficient at filtering out particulate matter, according to Vance. The only difference between N95 and KN95 masks is the standards used to test efficiency, as KN95s are produced by different countries.

Vance and her colleagues have been testing N95 and KN95 masks in their lab and have found that both have very high filtration efficiency.

“These are both very efficient masks; I would trust them both,” Vance said.

Smoke from wildfires can be in high in PM2.5, which indicates how many particles sized 2.5 microns and under are floating in the air we breathe.

Exposure to high amounts of smoke can quickly result in symptoms such as itchy or irritated eyes, coughing, chest pain, irritated sinuses, wheezing, and a fast heartbeat, according to the Centers for Disease Control and Prevention (CDC).

PM2.4 particles that are inhaled into the lungs over time may also lead to a host of health issues, such as an increased risk of:

Your standard cloth mask won’t offer much protection when it comes to wildfire smoke, according to experts.

“When it comes to wildfires, the story is completely different,” Vance said, comparing the use of cloth masks for protection against wildfires to protection from COVID-19.

Wildfire smoke particles are much smaller — about 10 to 100 times tinier — than respiratory droplets, according to Vance.

Cloth masks aren’t able to efficiently filter out these hazardous particles. They also often have gaps on the sides and around the nose where polluted air can seep in, inhale, and enter your lungs. They’re beneficial but not as good as an N95 mask, Lang said.

The structure and type of fabric the cloth mask is made of matter, according to recent research on effective face masks from Colorado State University.

Dual and triple-layer woven cotton masks are better at filtering out particles, compared with other fabrics.

“When you’re talking about fabrics, you want something that has tightly woven, non-stretchy material and multiple layers of it rather than a single layer,” Vance said.

You can also buy a filter — like a furnace filter or MERV 13 filter — and build it into your cloth mask.

Vance recommends ensuring the filter is layered within the entire mask, rather than just part of the mask.

A well-built cloth mask with a center filtering layer can substantially lower your risk, says Lang.

If you live in an area with poor air quality, it’s best to stay inside whenever the Air Quality Index (AQI) reaches unhealthy levels.

“If you don’t have to be outdoors, stay indoors,” said Lang.

You can monitor your local AQI levels on AirNow or PurpleAir. If the AQI ranges from moderate to hazardous, avoid going outside. A mask should really be worn if the AQI is higher than 100, Vance says.

It’s also wise to reduce any opportunities for the air to creep inside — close your windows and doors and consider sealing off any potential air leakage sites. “A lot of the outdoor pollution eventually makes it indoors and affects the indoor (air) quality,” Vance said.

Vance recommends purchasing an inside air purifier that contains HEPA filters. Avoid ionic air filters, Vance says, as they may actually produce some byproducts that you don’t really want to breathe in.

The DIY box filter solution — which can be made quickly with a box fan, filter, and duct tape — is another more affordable option, says Vance.

“Some people will continue to experience difficulties even with filtered air indoors, as filters do not ‘purify the air,’ only reduce the concentration of particles,” said Lang.

If you try these methods out and your respiratory system is still irritated, “The best approach is to leave the downwind areas until the fire is controlled or the winds change,” Lang said.

Health experts say an N95 mask is your best bet for protecting yourself from both the novel coronavirus and wildfire smoke.

Research shows KN95 masks can be just as effective.

Cloth masks, though effective at protecting yourself and others from COVID-19, aren’t going to offer much safety from the hazardous particles produced by wildfire smoke.