A BBC report this week put the number of active Canadian wildfires above 800, with smoke columns thick enough to trigger air quality alerts across a wide swath of the northern United States. If you live anywhere from the upper Midwest to the mid-Atlantic, the air coming through your window screens right now may be carrying fine particulate matter — PM2.5 — at concentrations that carry real health consequences for children, older adults, and anyone with asthma or cardiovascular disease.

This is not a one-summer anomaly. Wildfire smoke events that reach the continental US have become a regular July and August feature over the past several years. The question is no longer whether it will happen; it is whether your household is set up to weather three to ten days of degraded air without much scrambling.

What's actually changing

The practical issue with wildfire smoke is that most American homes were not built to keep it out. A house with average air leakage will see its indoor PM2.5 climb toward outdoor levels within a few hours of a heavy smoke event, unless something is actively filtering the air. Central HVAC systems help only if they have a high-quality filter and the system is actually running in recirculation mode. Window AC units with an "exhaust" setting actively pull outdoor air in.

The second issue is that most households have no way to know what their indoor air quality actually is. Feeling fine is not a reliable signal — PM2.5 is invisible and odorless at moderate concentrations. The irritating smoky smell that cuts through is a separate set of compounds; absence of smell does not mean absence of particles.

The third issue is supply. When a smoke event hits a metro area, N95 masks and portable air purifiers sell out within 24 to 48 hours at local retailers. Families who wait for an active alert to go shopping will find empty shelves, the same pattern that played out during the 2023 Canadian wildfire season and again last summer.

What we'd actually do

Check your HVAC filter and replace it if it's been more than 60 days. Most central systems can accept a MERV-13 filter, which captures a meaningful fraction of PM2.5. The upgrade from a basic MERV-8 to MERV-13 costs roughly $10 to $20 per filter. Call your HVAC manufacturer or check your unit's manual to confirm your system can handle the increased resistance — some older units cannot — but for most residential systems installed in the last 15 years, MERV-13 is fine. Set the system to recirculate rather than drawing in outdoor air.

Buy one portable air purifier with a true HEPA filter for the room where your family sleeps. A purifier rated for 200 to 300 square feet costs $80 to $150 when purchased outside a smoke event. During a smoke event in a major metro area, that same unit goes for twice the price if it is available at all. One room of genuinely clean air is what epidemiologists call a "clean room" strategy, and it is the single most effective low-cost intervention for smoke exposure in residential settings.

Stock a two-week supply of N95 or KN95 masks and know who in your household needs them most. A box of 20 N95 respirators runs about $20 to $30 at normal retail. They are not for walking around town; they are for the 15 minutes you spend moving between your car and your front door, or for household members who must commute. Surgical masks and cloth masks do not filter PM2.5 effectively — the filtration layer is the point.

Download an air quality monitoring app and learn what the AQI numbers mean before you need them. AirNow.gov is the EPA's free, no-account-required platform. An AQI above 100 means sensitive groups should limit outdoor time. Above 150, everyone should limit strenuous outdoor activity. Above 200, the clean-room strategy becomes relevant for healthy adults too. Knowing this in advance means you are making decisions from information rather than from anxiety.

If you have anyone in your household with asthma, COPD, or a heart condition, talk to their doctor now about an action plan. Wildfire smoke is not just an inconvenience for these individuals. PM2.5 at elevated concentrations has measurable effects on cardiac and pulmonary function within hours. Knowing whether to adjust medication, when to leave the area, and what symptoms warrant emergency care is a conversation to have before the air turns orange.

The bigger picture

Wildfire smoke is the kind of slow-moving, recurrent disruption that preparedness culture tends to underweight because it is not cinematic. It does not feel like a disaster. It feels like a bad week. But three to five bad weeks per summer, compounded over years, adds up to real health consequences, especially for kids whose lungs are still developing and for elderly relatives who may be dismissing symptoms they should not ignore.

The goal here is not a bunker. It is a household that does not have to panic-shop when the AQI spikes, that sleeps in filtered air, and that knows the difference between "uncomfortable" and "medically urgent." That is durability. It is boring, it is cheap, and it works.