Skip to Content

CSU research shows N95 masks can protect against wildfire smoke

FORT COLLINS, Colo. (KRDO) - A new study by a team at Colorado State University shows some of the masks we've been using to protect ourselves against coronavirus can also protect our lungs against wildfire smoke.

Last year, research scientist Jack Kodros and a team at CSU were testing masks and respirators as a part of ongoing efforts by the state to look into protection against COVID-19. During that research, Kodros got the idea to study mask effectiveness during another crisis that often affects Colorado.

“I had a lot of friends ask if masks would be helpful for wildfire smoke," said Kodros. "In Colorado, we now experience this every single summer. People started to think, can we wear masks and have double protection? I noticed there wasn’t really a lot of quantitative guidelines out there about what masks may be protective against wildfire smoke.”

For this research, which is now published in GeoHealth, the team used a pump that sucks in air to a flow rate similar to what we breathe in when we’re sitting around or talking. They then simulated the flow of air through a variety of masks: N95 respirators, surgical masks, and fabric masks, and measured how many particles made it through the mask.

“What we found is that the N95 can reduce the upwards of 95% of wildfire smoke-sized particles,” said Kodros.

This is because well-fitting N95 respirators with a leak rate of only 5% were shown to reduce someone's exposure by a factor of 16. That essentially takes the air you breathe from the smokiest days in Colorado to a normal day of very low concentrations. 

“It would be very effective at reducing exposure, so long as you’re wearing it properly, and that is a key factor," said Kodros. "If you don’t wear it properly, of course, you will have less benefits."

As for other kinds of face coverings, the cloth masks that have been very popular during the pandemic didn't seem to hold up as well against wildfire smoke.

“What we found is the cloth masks did not offer all that much protection against wildfire smoke, because as the particles come in, they are usually able to go right through the mask," said Kodros. "The fabric masks are not good at filtering them out, and sometimes these masks don’t always fit properly."

Surgical masks actually did a great job at filtering the particles, often up to 90 percent. However, they are not intended to fit over your face tightly like an N95 respirator, which lets pollution slip in.

“When you take into account the fit of that mask, the actual benefit or reduction in exposure, is dramatically reduced," said Kodros. "It’s actually similar to the performance of the cloth mask."

A case study was also conducted using data from Washington State's fire season in 2012. Hypothetical questions were asked, like what would be the expected reduction in hospital admissions due to wildfire smoke exposure if some people were wearing masks? The team was able to estimate that the use of N95 respirators could reduce respiratory hospitalizations caused by wildfire smoke by 22-39%. 

While Kodros believes this new data will be helpful for those who have to go outside when air pollution is dangerously high, he also admits there is a bigger issue at hand that needs to be addressed.

“I think the discussions we are having about wearing masks, should be a red flag to pay attention to our environment," said Kodros. "Because wearing a mask is one way to limit exposure, but it’s not going to limit wildfires themselves. There’s an underlying cause, because of our increase in climate change we’re having more severe wildfires."

Kodros stresses these findings, especially about cloth and surgical masks, must only be applied to the research regarding wildfire smoke. His team has found cloth masks do limit the transmission of COVID-19. With coronavirus, masks limit the emissions of our own droplets, and the size of particles for COVID-19 are different than particles of wildfire smoke.

Article Topic Follows: News

Jump to comments ↓

Author Profile Photo

Mallory Anderson

BE PART OF THE CONVERSATION

KRDO NewsChannel 13 is committed to providing a forum for civil and constructive conversation.

Please keep your comments respectful and relevant. You can review our Community Guidelines by clicking here

If you would like to share a story idea, please submit it here.

Skip to content