Do N95 masks work to protect you and your family from wildfire smoke?


Dr. Michael Mehta of TRU wearing a Vogmask. Yes, I've heard the jokes about Darth Vader and Silence of the Lambs.


Over the past two years people in many parts of British Columbia have been exposed to unusually high levels of particulate pollution from wildfires.

The messaging from the BC Centre for Disease Control (BCCDC), and public health officials from Interior Health and other publicly funded health care providers, has been mixed and noticeably negative about the benefits of wearing N95 respirator masks as a risk reduction measure.

In a recent article by Ashley Legassic of CFJC Today, she quoted Interior Health Medical Health Officer Dr. Kamran Golmohammadi as follows: 

"They require fitting," he says. "In other words, it has to be tight on the face. So people with facial hair, small children and people who cannot fit (the mask) properly... will not benefit from these masks and there are alternative ways and more effective ways of protecting people from these particles."

To limit your exposure to wildfire smoke — Golmohamaddi suggests spending time in areas with good indoor air quality like gyms, malls and libraries, consider purchasing a clean air filter for your home, and taking it easy if you need to spend time outside.

Sarah Henderson from the BCCDC stated:

"It's harder to breathe when you're wearing an N95 and we know from studies that it's not so bad for young people, but the older you are the harder it becomes to breathe through a facial respirator," she says. "So if you're having difficulty breathing in the first place, wearing a facial respirator may not help the situation."

"They do not perform well when they are wet or moist so if you're sweating in your mask and creating quite a lot of humidity, that will deteriorate the quality of the mask and it will stop filtering as well."

This messaging is clearly designed to discourage use of masks. Are they right?

The article seems to be addressing single use particulate respirators of polypropylene material such as offered by 3M.

Cloth face masks such as those offered by Vogmask, and tested for reusability, offer carbon filter media in addition to highly efficient particle filtering to address particles in wildfire smoke.

As the article correctly stated, the filtering efficiency depends on a proper fit. The N95 filter in Vogmask (and other high quality masks) measures in the lower 1/3 of the safety range (10 of allowable 30) for breathing effort.

Also the carbon filter acts as a dessicant to keep the mask at lower humidity. 

The exhale valve also serves to facilitate exit of moisture and CO2 from the interior of the mask.

No mask is 100% efficient, and fit is important to filtering percentage, but health providers all over the world have confirmed that good quality masks will help to keep particle exposure minimized.

Why would Interior Health and the BCCDC not discuss these issues and only focus on the efficacy of low-cost respirator masks when there are clearly superior and more effective options available?

I have three theories about this.

First, Western culture is not used to - or comfortable - with people wearing protective devices in public. In countries like China, Japan, and India, wearing a mask to protect yourself is the norm, and in many of these cultures people wear masks to protect others from respiratory infections.

Second, there is likely a fear amongst health officials in British Columbia that a strong reaction to air pollution associated with wildfires, as symbolized by wearing masks, may awaken a sleeping giant. In many parts of B.C., air pollution is a lot worse than most of us realize. Our cities including Kamloops, Prince George, and other towns and cities with pulp and paper operations have horrible air pollution yet the messaging is calm and reassuring. Residential wood burning creates parallel and often worse problems in rural communities. Waking people up to the spectre of air pollution will likely lead to a call for enhanced monitoring, stricter limits of pollutants, and fines and other mechanisms to make polluters pay. 

Third, the thousands of men and women who fight forest fires in this province do so - in incredibly polluted environments - without respiratory protection. I fear a wave of COPD, asthma and other diseases from their courageous and necessary work. It's my understanding that they do not usually wear masks in these environments either, and that they are actively discouraged from doing so. Our province is sitting on a ticking time bomb in terms of these health impacts, and encouraging everyday British Columbians to wear masks may trigger a class action lawsuit one day since that messaging is clearly inconsistent with how fire fighters in the field are being treated.

In short, wearing a mask is a personal choice. If you've tried a low-cost N95 mask, you probably didn't enjoy the experience. I recommend investing in a higher quality mask like the Vogmask. Perhaps these kind of masks will one day become the new sunglasses. I sure hope not.


Michael D. Mehta, Ph.D.



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