Staying safe in wildfire smoke

General

You may not consider all of the tips discussed to be appropriate for you. We all have different risk profiles and protection available to us. Some tips are better suited to heavier local smoke than you may be experiencing, while others are best utilized when a smoke event occurs alongside a heat event, which is common in the west.

In addition, any action you take which mitigates your risk is better than taking no action, regardless of its absolute efficacy. The more mitigation you undertake, the better off you will be - this has been called the “swiss cheese” defense model. So picking and choosing is quite valid! At the very least, please keep track of the AQI in your area. For the particulates it measures there is no safe level of exposure for anyone in any condition - all mitigation is helpful.

Understand the harm

Smoke - any smoke - is dangerous to breathe. The biggest danger comes from a class of particles we call PM2.5 - those which have a size of 2.5 microns or smaller. Pollutants in this range are difficult for the lungs to clear. They accumulate over time - all exposure increases your lifetime risk of lung disease, cancer, and chronic respiratory conditions such as COPD. PM2.5 pollution is measured with the Air Quality Index, or AQI - in general, everyone should be masking and limiting exposure when their local AQI is greater than 100 or so - fresh air typically rates in the 20s to 30s. Health effects can be noticeable at AQI levels as low as the 50s.

Environment and Climate Change Canada (ECCC) also uses the AQHI. This is a simplified scale which has gradations in risk exposure for levels from 1 to 10, but which can rise to much higher numbers to indicate the severity of air quality disasters - something wildfire smoke readily qualifies as.

Air pollution generally is linked to a large variety of chronic conditions which reduce your health and well-being. Protecting yourself and your loved ones from pollution is important - particularly in young children whose bodies and lungs are still developing.

Tools to stay informed

The danger posed by smoke changes throughout the day, so timely information is important for decision-making. Online resources are great for this.

Purple Air

A map showing air quality monitoring stations around the world. The sensors shown are inexpensive and hosted by institutions, businesses, and random folks who are interested in surfacing this data to the world. This map allows you to quickly see what the real-time AQI is in your area.

Note that, by default, Purple Air doesn’t apply any weighted correction to the AQI it displays. This means that measurements on Purple may show somewhat higher numbers than other resources. The top-left box on the map display allows you to pick the US EPA correction equation or any others of interest.

FireSmoke.ca

A map which depicts large fires and smoke plumes in North America at present, as well as where they are expected to move in the near future. Even during a serious smoke event, the actual concentration of dangerous particles around you can change substantially throughout the day. Try to schedule your outdoor time for periods when the smoke is lighter.

fire.airnow.gov

Another readily browsable map resource which shows both air quality readings and wildfire smoke. The smoke layer seems to be consistently of a lower resolution than FireSmoke.ca, but is generally useful. This map combines Purple Air’s sensor network with other networks and may be more comprehensive. US EPA AQI correction is applied by default and the sensors which are shown have been vetted.

Other

Your phone’s weather app likely includes information on air quality. Many other apps are also available which make use of the same resources as tools listed above - your goal should be to find something that works for you that you can make a habit of checking while the smoke lingers.

Stay hydrated

You’ll need more water than normal to cope with the adverse conditions. Your lungs use water to make mucous, which is used to clear accumulated particles out. The sooner they can do this, the better.

You may feel sick

Smoke exposure leads to headaches, fatigue, anxiety, difficulty breathing, and many other symptoms. Those who suffer from allergies or asthma should expect these conditions to worsen while the smoke lingers. Everyone can be affected by smoke exposure, even individuals who consider theirselves healthy.

Don’t sweat the smell

Even with a well-fitting mask or portable respirator, you may find yourself smelling wildfire smoke. Many of the odors our noses can detect are too small to be reliably filtered - the static charge present on meltblown fabric masks (KN94, KN95, N95, etc) can prevent some smell intrusion but not all. Particles capable of making it through this kind of mask likely do not pose a risk to you.

Correspondingly, the air quality can be incredibly poor without any smell.

It isn’t just wood smoke

Wildfires quickly expand to consume everything in their path, including vehicles, homes, and other buildings. Burnt material joins the rest of the smoke. For this reason it’s much more dangerous than, say, being around a campfire.

Indoors

Keep windows closed!

The fewer particulates which enter your home, the better. While few buildings are truly air-tight, windows are deliberately effective for air exchange. This may seem obvious to some, but far too often folks fail to take this extremely important and simple precaution.

If you need fresh outdoor air - for example, because CO2 is accumuluating - try your best to only allow it to come through a filter. Furnace filters can be found at many stores or ordered online. Cover any gaps left on the window and seal all of the seams with painter’s tape, which can be easily removed without residue later.

Block outdoor air

Doors and windows can be sealed off with painter’s tape if they aren’t in use. It is designed to come off easily after the fact, without damaging surfaces.

In heavy smoke, you can use soaked rolled-up towels to cover door thresholds.

Try not to run exhaust fans, such as those in bathrooms and kitchens, when it can be avoided. These cause your indoor space to have negative pressure relative to the outdoors, drawing in more outside air through cracks and crevices.

Filter your air

If your home (or apartment building) has a central air circulator (such as a furnace) which uses filters, see if you can find HEPA-rated filters that fit, or get the super to do so. Then, run the circulator fan - most furnace control panels allow you to do this without heating or cooling, though adding either to the mix is also fine. This will handle most of the burden for you.

Standalone HEPA-rated air purifiers are widely available. Anything which meets this standard will make an important difference in your indoor air. Purchase only from a reputable vendor - steer clear of third-party sellers on sites like Amazon and Walmart.

You can also make a DIY air purifier, also known as a Corsi-Rosenthal box: a relatively cheap (for its effectiveness) construction of furnace filters and a box fan which was popularized in the early pandemic. See below for a guide and links to further information. There are many designs with trade-offs in cost, clean air delivery rate (CADR), and space. The simplest iteration - a filter taped to the intake side of a fan - is still much better than nothing.

Humidity helps

Water is heavier than air and likes to precipitate out of it when it can. Smoke particles, which act as nucleation sites, are exactly what water needs in order to do this. A humid indoor environment forces them out of the air and onto surfaces where they can’t harm you as easily.

There are many ways to humidify your indoors. Commercially available humidifiers work well so long as you maintain them and keep them clean - unmaintained humidifiers can quickly become dangerous mold hazards. Alternately, any standing water left out will evaporate at its surface and humidify the air. Consider filling up buckets, pots, and/or pans and leaving them out of reach of children and pets. This can also be accomplished by filling your bathtub or sinks. Use cool water.

You can also raise the humidity in combination with other home tasks, such as by taking a shower but not using the vent fan. Dishwashers can be set to skip their drying phase and then opened to air dry, and clothes can be hung up out of the washer - these latter methods are unfortunately less useful in wildfire smoke, because you could end up with sooty dishes and clothes. Consider washing and hanging a less-loved blanket or some other alternative fabric - be sure to clean it well when the smoke passes.

Outdoors

Wear a mask

Ideally, a fit-tested N95 or better. KN95s, KF94s, and similarly-rated masks are nearly as good - just be aware that ear loops can’t really guarantee the same seal as head loops. In a pinch, a cloth mask, a tightly-wrapped article of clothing, or any kind of physical barrier you can breathe through is better than nothing. It’s all about reducing exposure.

In particularly heavy smoke, fabric masks like those rated N95 may clog too quickly to be safe to use. If you find that it quickly becomes difficult to breathe through such a mask, bring extras and swap them out as needed. Pay close attention to how you feel to be sure that you are getting enough air. In this situation it likely makes sense to acquire an elastomeric respirator (such as one rated P100) - these use multi-layer filters that are much more effective at tackling prolonged and heavy particle loads. They also form an excellent seal with your face, giving you peace of mind.

Limit activity and slow down

Exertion of any kind increases the amount of air your body needs to function. This correspondingly increases your exposure to the dangerous particulates in smoke. Skip your bike ride, abbreviate your dog walk, do your best to limit the time you spend outside. The smoke will pass.

Plan for things to take longer. You may find yourself surprised by how quickly you feel out of breath, even during tasks that are usually easy for you. Take your time when walking or wheeling. Take breaks often. Try to stick to low-energy activities. Reduce your expectations - it’s okay if things feel hard to accomplish. Being inundated in smoke is a serious thing!

Keep pets safe

The air is as dangerous to them as it is to you, and they can’t take any action to protect themselves. Some dog owners have had luck with dog masks, but these should be used with caution because they can stop your dog from panting - their main way of keeping cool.

Cover up

If you must be outdoors, cover up. Long shirts and pants keep soot and ash away from your skin, where it can be an irritant. Glasses and goggles can protect your eyes. A hat will protect your head. Anti-inflammatories and antihistamines can both be useful for moderating the symptoms of smoke exposure. Definitely bring your inhaler along if you have one.

When you return home, change your clothes and collect the dirty clothes where they won’t get moved around (kicking up ash and soot) prior to cleaning. You can optionally keep clean damp washcloths in your fridge or freezer and use them to wipe down exposed skin on your limbs and face - it feels really nice and will clean you up.

Cleaning up later

Indoor surfaces

After the smoke has passed, you should clean surfaces in your home that may be harboring soot and ash. Carpets and soft furniture should be vacuumed with a machine which has a HEPA filter. Countertops, appliances, and hard furniture should be wiped down with a damp cloth - use a light touch to prevent the ash from causing scratches. Any lingering particles can become airborne again after settling, so undertaking this step saves you from future lung irritation. Cleaning up before the smoke has passed should be avoided - you’ll kick up ash when the air quality is already poor, and you’ll likely have to clean again after the smoke has passed.

Filters

All air filters should be inspected. If you experienced heavy soot, many or most of them will need to be replaced - soot and ash in your filter reduces its efficacy and can become dislodged later, posing a health risk all over again. This is true for air filters, HVAC filters, and even the air filters - engine and passenger - in your car.

Clothes and other fabrics

Your typical laundry practices will likely be sufficient to clean clothes and blankets that only received mild indoor exposure. If they were in outdoor air, or the smoke was particularly bad, they may need additional attention. There’s many ways to tackle this:

• Use vinegar in place of fabric softener - use up to a half cup per laundry load, either via the fabric softener dispenser (where the machine will dilute it as it uses it) or, in top-loading washers which don’t have a dispenser, directly into the drum during the rinse cycle, when it will immediately be diluted by the rinse water. Don’t add it to the detergent drawer and don’t add it during any other cycles - mixing vinegar with detergent causes both substances to perform poorly, and undiluted vinegar in contact with your fabrics can damage them.

• A sprinkle of baking soda in the detergent dispenser (or added alongside the detergent to top-loading machines) boosts the power of the detergent and works as an effective odor remover.

• OdorKlenz and similar products are widely appreciated as “last resort” smell removers. They can be even more effective with a pre-treatment soaking / laundry stripping phase.

With all additives, you may need to do an extra rinse cycle to clear lingering residue.

Outdoor surfaces

Outdoor surfaces you are responsible for may need to be cleaned, too - ash and soot can contain sodium hydroxide, which becomes lye in the presence of water. A hard rain will generally clear out surface accumulations, but a soft rain, mist, or fog could cause concentrated ashy droplets to form that can substantially damage painted surfaces and clear coats. Hosing the surface down (or inundation with a bucket) generally takes care of this, because any resulting lye is too dilute to cause harm. Cars can be hosed down in a pinch, but it’s better to take them to a touchless car wash where the resulting pollution is captured rather than allowed to enter groundwater. Brush-style car washes can rub the ash into the clear coat and scratch it.