Wildfire Smoke and Sleep: What Helps, and What Needs CBT-I

You wake at three. Your throat is dry, your nose is blocked, and the window has been shut for nine days because the air outside is worse than the heat inside. You lie there and start counting the hours you have left.

Multiply that by a province. British Columbia is partway through another hard fire season, with air quality warnings shifting between the Interior and the South Coast as the wind changes. For a lot of people here this is the fourth or fifth summer in a row that has gone like this.

Smoke can wreck a night. It is a poor explanation for insomnia that has been running since July. Those are different problems and they take different fixes.

Smoke Disrupts Sleep Through Your Airway

Wildfire smoke is mostly fine particulate matter, and fine particulate matter irritates the lining of your nose and throat. Irritated tissue swells. A swollen nose means you breathe through your mouth, and mouth breathing during sleep means a drier throat, more snoring, and more of the brief arousals you do not remember but that fragment the night anyway. Add coughing on top and you have a mechanically worse night that has nothing to do with your relationship to sleep.

Researchers surveyed 2,084 adults in Canberra after the 2019 to 2020 Australian bushfire season, a stretch where smoke sat over a major city for weeks. Around half reported poorer sleep they attributed to the smoke, split between disrupted or poor sleep at 37.2 per cent and fatigue at 32.5 per cent. Nearly everyone, 97 per cent, reported at least one physical symptom, usually eye or throat irritation. Anxiety attributed to the smoke ran at 45.3 per cent.

The study has limits. It was cross-sectional, everything was self-reported, and people were asked months afterward to attribute their own symptoms to smoke. Mailed invitations came back at 6.4 per cent, and respondents skewed female, older and more university-educated than the surrounding population. It counts how many people noticed, not how much sleep they lost.

Which is enough. A blocked nose costs you sleep. Smoke blocks your nose. Clear the air and the nose clears, and the sleep comes back within a night or two of the air improving. Sleep that does not come back was never about the smoke.

Disrupted Sleep and Insomnia Are Different Problems

Sleep disruption is what happens when something interferes with sleeping. Noise, pain, a new baby, a blocked nose. It is proportionate to the cause and it clears when the cause clears. You do not need treatment for it. You need the cause to stop.

Insomnia disorder runs three or more nights a week for three months or longer, it produces daytime consequences, and it happens despite adequate opportunity to sleep. The defining feature is that it outlives whatever started it. If you can tell the difference between a rough patch and insomnia, you are most of the way to knowing which kind of help you need.

Clinicians usually think about insomnia in three parts: what made you vulnerable, what set it off, and what keeps it going. Smoke is a plausible candidate for the second. It is a bad candidate for the third. Particulate matter does not follow you into February.

What does follow you into February is everything you did to cope with a terrible month. Going to bed at nine because you are exhausted and hoping to bank some extra. Lying there awake for two hours because you got in before you were sleepy. Sleeping until ten on the weekend to catch up. Staying in bed after waking because at least you are resting. Each of those is a reasonable response to a bad stretch, and each of them, repeated for a few weeks, teaches your body something you did not intend to teach it. That is the part that persists, and that is the part CBT-I treats.

A Four-Day Smoke Event and a Hazy August Do Different Things

Six weeks of smoke means six weeks of closed windows and hotter bedrooms. It means cancelled outdoor exercise. It means less daylight, because haze cuts the light reaching you even at noon. It means more time indoors, more screens, and a schedule that quietly comes apart. Those are the things that turn a bad summer into a sleep problem that is still there when the rain comes back. They are also, unlike particulate matter, things that respond to treatment.

British Columbia Reports Air Quality Differently From the Rest of Canada

Canada's Air Quality Health Index combines fine particulate matter, ozone and nitrogen dioxide into one score. During the 2017 fire season it became clear the standard formula was underreporting the risk on smoky days, because averaging particulate matter with two pollutants that were not elevated dragged the number down. BC responded by developing an adjustment called AQHI-Plus, piloted in 2018 and adopted province-wide in March 2021 after two peer-reviewed studies supported it. The province now runs both calculations and reports whichever is higher, so on a smoky night the number you see is driven by particulate matter alone.

The BC number is more responsive to smoke than what someone in Ontario is looking at. Check it in the evening, not in the morning, because the decision it informs is whether to open the bedroom window overnight.

Closing the Window Against Smoke Makes the Bedroom Hotter

Sealing the house is the right move for air quality and the wrong move for temperature. A hot bedroom has better evidence behind it as a sleep disruptor than moderate particulate exposure does.

Most BC housing was built for a climate that no longer reliably shows up, and a lot of it has no air conditioning. So you end up choosing between smoke and heat on the same night.

• Cool the room during the day while it is sealed, using whatever you have, rather than relying on night ventilation you may not be able to use.
• A fan moving air inside a closed room helps you without importing smoke. A fan in an open window does the opposite.
• Turn off bathroom and kitchen exhaust fans during heavy smoke. They pull outdoor air in to replace what they push out.
• If the evening index has dropped and the night is cool, open up. The choice is nightly, not seasonal.

Filtration Does the Most Work

Make the bedroom the cleaner-air room, keep the door shut, and filter it.

Health Canada's guidance on cleaner air spaces sets the standard.

• Size the unit to the room using its clean air delivery rate, aiming for filtered airflow of at least two to three times the room volume per hour. The rating is usually on the box.
• Insist on a certified true HEPA filter. Units marketed as HEPA-type or HEPA-like are not the same product and will not reliably capture the smallest particles.
• Avoid ionizers and anything that generates ozone. Ozone is itself a respiratory irritant, and you are trying to reduce the load on your airway, not change its composition.
• A do-it-yourself box fan filter using a MERV 13 or higher furnace filter is a legitimate substitute and costs a fraction of a commercial unit.
• If you have forced air, run the system on recirculation with a good filter rather than drawing in outside air.
• Buy before the season. Units disappear from shelves the week the smoke arrives, every year.

A CPAP machine draws room air. If you use one, run it in the filtered room and check the filter more often than usual during smoke.

CBT-I Treats What the Smoke Leaves Behind

The following is a composite drawn from several presentations and does not describe any individual client.

A woman in the Interior, mid-forties, comes in during February. Her sleep fell apart in July when the smoke settled in and it has not come back. She spent August going to bed at nine because she felt wrecked by eight, then lying awake until midnight. She started sleeping in on weekends. By October the smoke was long gone and she was still lying awake, and by then she had added the worry that something might be wrong with her.

Nothing was wrong with her. The smoke started it and her entirely reasonable coping strategies finished the job. Her bed had become a place she went to be awake in, her sleep window had stretched to eleven hours to catch four or five, and her drive to sleep was spread too thin to do its job. None of that is treated with an air purifier in February. It is treated by rebuilding the association between bed and sleep and by compressing the window until the pressure returns, which is what CBT-I does.

During an active smoke event, when you are being woken by coughing, the problem in front of you is not psychological and it does not want a psychological answer. Filter the room. That is the intervention. Reaching for a sleep technique when the answer is a HEPA filter is the same error as trying harder to sleep.

One part of smoke season does belong in the therapy room. Checking the fire map at eleven at night, refreshing the index, reading evacuation alerts in bed. That is not a smoke problem, it is an arousal problem wearing a smoke costume, and it belongs with the rest of the bedtime mind-racing material.

For Some People Smoke Season Is a Medical Issue

If you have asthma, COPD, another respiratory condition, or diagnosed sleep apnea, smoke season is a management question for your physician before it is anything else. The same is true if you are getting chest tightness, a persistent cough, or shortness of breath that is new. HealthLink BC at 8-1-1 is staffed around the clock if you want to talk it through with a nurse. N95 respirators have been distributed free in some Interior communities during heavy smoke periods, so ask locally.

None of that is counselling work, and no amount of good sleep technique substitutes for it.