Defense against smoke: With wildfires raging, N95s return to forefront for filtering out harmful particles

Many people first heard about N95s when COVID-19 spread in 2020, and the masks’ shortages pushed the priority to health care workers for protection from the virus. With ramped-up production this year and rising COVID-19 vaccinations, the N95s – also called respirators – are found more readily at home improvement stores.

This summer and into early fall, the respirators can offer protection for another reason: wildfire smoke. Spokane skies have filled with smoke already. Experts consider the N95 mask – if used properly – as a best defense against breathing in smoke’s harmful particles for those who must go outdoors, said Nikki McCullough, a 3M respiratory health scientist who tests and develops N95s.

“We do human subject testing on N95s continuously to design the respirator to form a seal to a lot of different face types,” McCullough said. “The importance is the particles we’re talking about that are airborne now with the smoke are so small that unless there is a high concentration, you can’t see them. If there is a gap between the edge of the respirator and your face, those particles are going to go right around that gap.

“That gap can even be caused by one day of (beard) stubble because the particles we’re talking about that remain airborne are less than 100 microns.” A micron is a unit of measure in the metric system that equals one-millionth of a meter. Many experts refer to smoke’s particulate matter in micrometers, with the fine particles generally 2.5 micrometers and smaller.

The average human hair is about 70 micrometers in diameter – making it 30 times larger than the largest fine particle. Wildfire smoke can travel hundreds of miles. The Centers for Disease Control and Protection says a certified N95 filters out at least 95% of particles in the air – large and small – if the N95 is worn properly for minimal leakage around the edges when the user inhales.

McCullough offers tips for proper use and wear of N95s in smoky conditions. People might be unaware of how much technology and science go into them, she said. “They’re designed to seal to your face so that when you breathe through it, the air goes through the filtered media,” McCullough said. That differs from a cloth face covering that typically has gaps and “are primarily to help contain what you sneeze and cough out.”

Know what to buy

Look on the product for NIOSH, meaning National Institute for Occupational Safety & Health certification. It should also have a printed N95, a manufacturer’s name and lot number. Regarding sizes, consider if you need a small or medium-large. However, McCullough said 3M designers strive to make many N95 models fit a wide variety of faces.

Also, watch out for a counterfeit product. NIOSH offers guidance on how to spot a fake. U.S. officials have fought this past year against the problem of counterfeit N95s that haven’t been tested or verified, posing a risk to users. “People should make sure the right markings are on the products, reading the packaging to make sure words are all spelled correctly, that there’s good grammar and there are things like that NIOSH-approved,” McCullough said.

Buy an N95 from a reputable retailer or company, she said. For additional information, 3M also has a website regarding fake N95s or how to report them.

Understand instructions

“Read the instructions that come with the package,” McCullough said. “Go to the manufacturer’s website. On 3M’s website, we have videos that help people know how to put on the respirator the right way.

“The main thing people should know is that most respirators have two headbands. It’s very important that people use both. You have one headband to go around the back of your neck and touch the skin. The other band should go right at the crown of your head. That holds the respirator against your face.

“If somebody is only using one strap, that respirator might not be touching the face all the way around.” The next step is properly forming a metal clip for the nose. Take two fingers from each hand and press down along the sides of the nose to form to the bridge.

“That’s important because some people have a really high nose bridge and some people have a really flat nose bridge, so that metal clip is designed to give you a customized fit,” McCullough added.

Don’t pinch the clip with one hand. “The reason we use two fingers to press it down is because if you pinch it, you might form a little triangle at the top – a peak – and the air can sneak through there, so you want to use two fingers and really form it down hard to your nose bridge so it fits to your nose bridge.”

Practice with a mirror

Try on a new N95 in front of a mirror first in a clean area of your home or office. “Is it straight on my face, are the headbands in the right places, do I see any gaps?” McCullough said. “Practice putting it on and wearing it for a little while in that clean environment. Just get used to how it feels breathing through it.”

Do that before you go outside. “Just spend 15 minutes practicing putting it on and getting used to wearing it, and then you’re more likely to get the full benefit of it.” Other tips include the following:

• For men, it’s important to shave every morning or right before wearing an N95, she said. “You don’t want to put it over a beard. Make sure there are no gaps and that the air is going through the filter media.”

• Avoid jewelry or scarves that might affect the seal and ensure that the mask touches your skin all the way around.

Know when to toss

“The good news with N95 respirators is that as they filter more particles, they actually become more efficient,” McCullough said. “You need to throw away the respirator primarily when you don’t feel you’re getting a good seal anymore, but also if it gets very dirty, gets damaged or becomes difficult to breathe through.”

Another reason to toss is if a strap breaks. Some users can make one last several days depending on the environment. Others replace an N95 by lunchtime each day, she said. People often wear N95s at industrial job sites or as consumers for at-home renovations, on mass transit, bad pollution days and during wildfire smoke.

Handle the N95 carefully. “We always recommend people wash hands before and after handling the respirator,” McCullough said. “Don’t crush it and shove it in a pocket. “They are designed to be worn multiple times but not forever. Sometimes, a strap will break or the nose clip just won’t push into your face anymore. Don’t try to fix it. Buy a new one. If you feel like it is not sealing to your face and if they’re are gaps, it’s time to get a new one.”