Wildfire Smoke Survival Guide: What Actually Protects You

Wildfire smoke is becoming a permanent feature of summers across western North America, Australia, and southern Europe. The PM2.5 concentrations during smoke events are among the highest most people will ever encounter.

Why wildfire smoke is different

Wildfire PM2.5 isn't just particle mass - it carries:

• Polycyclic aromatic hydrocarbons (PAHs) - some carcinogenic
• Volatile organic compounds (VOCs)
• Heavy metals from burning soil, vehicles, structures
• Ultrafine particles that go even deeper than standard PM2.5

Health effects of acute exposure: shortness of breath, asthma exacerbation, cardiac events, increased emergency room visits. ER admissions for cardiac events spike 20-40% during smoke events.

What actually works

Stay indoors with filtered air

• Close windows. Run HVAC on recirculate (not fresh air).
• Use a True HEPA purifier with CADR matched to room (see purifier guide)
• DIY: 20" box fan + 4 MERV-13 filters in a Corsi-Rosenthal cube. ~$80, hospital-grade results.

Wear N95 or KN95 outdoors

Cloth, surgical, and bandana masks don't work for PM2.5. N95 fitted properly cuts exposure ~95%. KN95 second best.

Reduce activity

Less breathing volume = less inhalation. Skip exercise, even indoors if your indoor air quality isn't filtered.

Stay hydrated

Helps mucociliary clearance. Won't dramatically lower harm but doesn't hurt.

What doesn't work (skip)

• Cloth/surgical masks - filter <50% of PM2.5
• Wet bandanas - same
• Burning candles or incense to "clear the air" - adds particles
• Standing in front of AC vents without HEPA filtration
• Vitamin C, charcoal pills, antioxidants - no clinical evidence
• HEPA-less ionic purifiers - generate ozone

24-hour exposure plan during a smoke event

| Time | Action | |------|--------| | 0h | Check forecast. AQI > 100? Skip outdoor activity. | | Morning | Run HEPA purifier on high in bedroom + main room | | Anytime outside | N95 fitted properly | | Driving | AC on recirculate, all windows up | | Indoor exercise | Only if HEPA filtration running | | Evening | Don't open windows. Even cool night air carries PM2.5. | | Sleep | HEPA purifier near the bed |

Vulnerable groups - extra care

• Asthma/COPD: have rescue inhaler accessible, follow action plan
• Pregnancy: stay indoors aggressively
• Children under 5: indoor refuge, skip outdoor activity entirely above AQI 150
• Elderly with cardiac conditions: indoor, monitor for chest tightness
• Outdoor workers: employers should provide N95s and rotate to indoor tasks

Track conditions

Smoke shifts hourly with wind. Track live AQI and check forecasts. Get email alerts for threshold crossings.

After the event

When AQI drops back below 50:

• Open windows, ventilate thoroughly
• Vacuum with HEPA-equipped vacuum (regular vacuums redistribute particles)
• Wash bedding, clothes worn outdoors
• Replace air purifier filters if they ran heavy duty for days

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Sources: US EPA Wildfire Smoke Guide, Health Canada AQHI guidance, BMJ wildfire smoke health reviews. Reviewed: 2026-05-02.