Small particles from wildfire smoke can lodge deep within your lungs, aerosol scientist explains

Hermits Peak is one of Alex Huffman’s favorite hikes in the world.

He grew up and spends time in the mountains outside of Las Vegas in northern New Mexico. His family has had a cabin in nearby Gallinas Canyon since before he was born.

“Some of my earliest memories are there,” he said. “That’s where I caught my first fish.”

He has been watching the daily updates on the Hermits Peak-Calf Canyon fire and said it’s very likely his family’s cabin is in the burn area.

As of Tuesday, seven large wildfires were burning across New Mexico, according to the NASA Earth Observatory. On Wednesday afternoon, wind carried smoke from wildfires in northern New Mexico all the way into the Texas and Oklahoma panhandles, and into eastern Colorado, according to the Forest Service’s fire and smoke map.

Huffman has been around enough wildfires to know smoke inhalation can be horrible.

He is an aerosol scientist and associate professor of chemistry at the University of Denver. He keeps thinking about what he could do to help, he said. He can’t come down and fight the fires, so instead, he’s trying to raise awareness about smoke inhalation, hoping people can use the resources they may already have.

N95 masks are a key piece of the fight against particle inhalation, whether it be from respiratory aerosols and things like coronavirus, or wildfire smoke.

Not long ago, the federal government sent a bunch of N95s to communities across the country.

However, reached by phone on Wednesday afternoon, staff at the Del Norte Pharmacy of Las Vegas said they were out of the free N95 masks. No other location in Las Vegas is listed on the CDC’s map of places where the government shipped N95s.

The pharmacy staff said there may be some left at the local Walmart, but they’ve heard there may be very long wait times to get into the store.

“Breathing smoke is bad. It’s not good for you,” Huffman said. 

It can cause acute health issues in the short term, but breathing wildfire smoke is never good in the long run either, he said, even if you don’t think of yourself as an at-risk individual.

“So the more we can keep people breathing lesser amounts of smoke, whether it be by being in a better place or preparing your home, or by wearing a good-quality mask like an N95, it’s going to help people’s health.”

High-quality masks protect against both coronavirus and wildfire smoke, Huffman said.

“There are no scientists or major public health agencies that I’m aware of at this point that aren’t supportive of the N95 being the most important tool,” Huffman said.

The science of wildfire smoke is not new, Huffman said, and has been around for many decades.

“We know exactly what to do about wildfire smoke and how to stop you from breathing it in, and an N95 mask is one of the best tools for that,” Huffman said.

What is an aerosol?

An aerosol is a little liquid or solid ball floating around in the air, Huffman said. These can include dust blown up from the ground by the wind, pollen and fungal spores from plants, and smoke particles from fires or the tailpipe of a vehicle, he said.

When you take a deep breath, you breathe in gas molecules like oxygen and nitrogen, but you can also take in particles or aerosols, he said.

Those particles are tremendously bigger than the oxygen molecules you breathe in to survive, Huffman said.

Particles in wildfire smoke are small pieces of burned or unburned fuels, or organic material small enough to stay suspended in the atmosphere for a really long time, just like the aerosols that come out of your mouth when you breathe, he said.

When you take a deep breath, you’re bringing in those particles along with the gas molecules. The oxygen and nitrogen come in and go back out, but the particles are large enough to get stuck in your lungs, he said.

Getting exposed to particles from wildfire smoke can irritate and inflame the lungs, alter immune function, and increase susceptibility to respiratory infections, likely including COVID-19, according to the CDC.

The science behind how N95s protect from wildfire smoke

Wildfire smoke needs to be dealt with, Huffman said, and a mask is an important tool to do that. It’s a big deal, it hurts you, and there’s something you can do about it.

Aerosol particles from your mouth when you breathe may have viruses in them, he said, and can vary in size from half of one micron to about 100 microns, he said. A human hair is between 50 and 100 microns thick.

The biggest component of the particles in wildfire smoke are smaller than a micron, he said, which is the size that gets deepest and lodges the furthest down into your lungs.

The smaller the particle, the better your mask needs to be to get rid of it, Huffman said.

When you breathe out, even a cloth mask can help filter out a good fraction of the biggest particles so they’re not spraying the people in front of you, he said. For the smaller particles, you still need a good mask, he said.

But when you breathe in, a cloth mask does a worse job, so you need an even better mask, he said.

Respirators like N95 do an excellent job of removing both big and small particles, because of the way their filtration media work and the way they fit tightly to your face, Huffman said.

“It’s not by accident that N95 masks do a great job of filtering out the small particles that are floating around because of wildfire smoke,” he said.

Good N95 masks are designed to have good filtration, fit well to your face and be breathable, he said. They should be able to do all three of those things, or else you’re just wearing the wrong mask, he said.

Cloth masks and surgical masks don’t do a very good job at filtering out smaller particles, Huffman said.

“They don’t do nothing, but they are definitely not the first choice,” he said.

Even if you can smell the smoke coming through your mask, the mask is still working, because the smell comes from gas molecules, Huffman said.

“The smell is gonna go straight through the mask, but the particle will be blocked,” Huffman said.

Filtering smoke out of indoor air

Another strategy is to filter the coronavirus out of the room you’re in, Huffman said. In an indoor environment, you may not necessarily want to wear an N95 all the time, especially if you’re sleeping, he said.

“If you can make that indoor space cleaner and safer, then it’s not as important for you to wear an N95 at all times,” he said.

One can buy a portable system with a high efficiency particulate air filter, but especially in a wildfire-affected area where people are being evacuated from their homes like in Las Vegas, N.M., it’s probably not going to  be easy to get a new filter unless you have it already, Huffman said.

There are Corsi-Rosenthal boxes or other do-it-yourself solutions that can do a really good job, he said. It may be possible to put one of those together for much less money than a commercial filter, he said.

If you can get a portable filter system of some kind, Huffman recommends putting it in a room in the interior of your home that doesn’t have direct input from the outside, sealing off the windows, and then spending as much time in there as you can, especially when the smoke is at its heaviest, he said.