Wildfire Nearby? What to Do During and After to Protect Your Health

TL;DR

Five actions, in order. If a wildfire is burning near you right now:

• Check AQI immediately on AirNow, PurpleAir, or IQAir — and keep checking every 30 minutes as conditions shift.
• Follow official evacuation orders without delay. If no order exists yet, use the decision framework below to decide whether to shelter in place.
• Seal your home — close every window and door, switch your HVAC to recirculate, and run a HEPA air purifier.
• If you must go outside, wear at minimum an N95/FFP2 respirator; P100 or FFP3 is strongly preferred for heavy smoke.
• After the fire, treat all ash as toxic, HEPA-vacuum every surface, and wait for an official "all clear" before resuming outdoor activity.

Step 1 — Monitor Air Quality in Real Time

The single biggest mistake people make during a wildfire is relying on what they can see. Smoke plumes travel. A clear sky at 9 a.m. can become an AQI-300 event by noon.

Use these tools — bookmark them now, before you need them:

• AirNow Fire & Smoke Map — the official U.S. EPA real-time map combining regulatory monitors and PurpleAir sensors. Updates every hour.
• PurpleAir — 35,000+ community sensors worldwide, updates every 10 minutes. Best for neighborhood-level changes during fast-moving smoke events.
• IQAir — global coverage, includes forecasts and wildfire event tracking. Good for planning the next 24–48 hours.
• Copernicus CAMS — European satellite-based fire and smoke monitoring. Essential if you're in Europe; shows smoke plumes crossing borders in near-real time.

What the AQI numbers actually mean for your actions:

AQI	Category	Outdoor Activity Recommendation
0–50	Good	Normal activity for everyone
51–100	Moderate	Sensitive groups should reduce prolonged outdoor exertion
101–150	Unhealthy for Sensitive Groups	Sensitive groups stay indoors; others limit extended outdoor activity
151–200	Unhealthy	Everyone limits outdoor activity; wear a respirator if you must go out
201–300	Very Unhealthy	Avoid all outdoor activity; P100/FFP3 respirator required for any outdoor exposure
301–500	Hazardous	Stay inside. Do not go out. Emergency outdoor exposure only, full respiratory protection mandatory

Set up AQI alerts on the IQAir or AirNow apps. You want a push notification the moment your local reading crosses AQI 100 — that's your first action trigger.

Step 2 — Evacuate or Shelter in Place?

This is the hardest call, and it's time-sensitive. Use this framework. If official authorities have issued an evacuation order, that overrides everything — leave immediately.

AQI Level	Distance from Fire	Official Order	Recommended Action
Any	< 5 miles / 8 km	Evacuation order issued	Evacuate now
Any	< 5 miles / 8 km	No order yet	Prepare to evacuate; monitor every 15 min
> 200	5–20 miles / 8–32 km	No order	Shelter in place; seal home
151–200	5–20 miles / 8–32 km	No order	Shelter in place; prepare go-bag
101–150	> 20 miles / 32 km	No order	Shelter in place; limit outdoor time
< 100	> 20 miles / 32 km	No order	Monitor closely; normal precautions

Key factors that can flip the decision:

• Wind direction — if wind is blowing the fire toward you, treat it as one category worse. Check wind direction on your weather app every 30 minutes.
• Rate of spread — fast-moving fires (driven by dry wind, steep terrain) can close 5 miles in under an hour. Don't wait for the order if you see the sky darkening rapidly.
• Road access — if your evacuation route could be cut off, leave early. A premature evacuation costs you a night in a hotel. A late one can cost everything.
• Vulnerable household members — if anyone in your home has asthma, COPD, heart disease, is pregnant, or is under 5 or over 65, apply the next stricter threshold in the table above.

Step 3 — If You Stay: Sealing Your Home Against Smoke

Sheltering in place only works if you actually seal the building. A house with gaps around doors and windows can reach outdoor AQI levels indoors within 30–60 minutes during heavy smoke.

Immediate actions:

• Close all windows and doors. Every single one, including the garage.
• Switch your HVAC/AC to recirculate mode (not "fresh air" intake). If your system doesn't have recirculate, turn it off entirely.
• Seal gaps with damp towels, tape, or draft stoppers — door bottoms, window frames, fireplace dampers (close them completely).
• Run a HEPA air purifier in the room where you spend the most time. A unit rated for your room's square footage, running on high, can cut indoor PM2.5 by 50–80%.

If you don't have a HEPA purifier:

A DIY box fan filter — a box fan with a MERV-13 furnace filter taped to the intake side — can meaningfully reduce indoor PM2.5. It's not as effective as a true HEPA unit, but it's far better than nothing. The EPA calls this the "Corsi-Rosenthal box" and has published instructions.

What not to do indoors:

• Don't burn candles, incense, or wood — you're adding indoor pollution on top of outdoor smoke.
• Don't vacuum with a standard vacuum; it re-suspends fine particles. Wait until the smoke clears, then use a HEPA vacuum.
• Don't cook on a gas stove for extended periods without ventilation — but don't open windows to ventilate either. Use an electric appliance or eat cold food.

Step 4 — If You Must Go Outside

Sometimes going outside is unavoidable: you're evacuating, dealing with an emergency, or getting your pets to safety. Wildfire smoke safety outdoors comes down to three things — the right mask, minimizing time, and timing your exposure.

Mask requirements — this is not the moment for a cloth face covering:

• Minimum: N95 (NIOSH-approved) or FFP2 — filters at least 95% of airborne particles. Better than nothing, but not ideal for sustained exposure in heavy smoke.
• Preferred: P100 (NIOSH) or FFP3 — filters 99.97% of particles. The standard for serious wildfire smoke safety.
• Fit matters as much as filter rating. A loose-fitting N95 leaks around the edges. Do a seal check every time you put it on: cover the mask with both hands and exhale sharply — you should feel no air escaping around the edges.

For unavoidable outdoor exposure during a wildfire air quality alert, a high-performance wildfire smoke mask with a certified nanofiltration membrane gives you the filtration level of P100/FFP3 in a lightweight, wearable format — relevant whether you're evacuating on foot, moving pets, or doing a quick perimeter check.

Time limits outdoors by AQI:

• AQI 151–200: Limit outdoor time to 30 minutes maximum, even with a mask.
• AQI 201–300: 10 minutes maximum. Move quickly and purposefully.
• AQI > 300: Do not go outside unless it is a life-safety emergency. If you must, P100/FFP3 is non-negotiable, and keep exposure under 5 minutes.

Practical tips:

• Move fast and with a plan — know exactly where you're going before you step outside.
• Avoid physical exertion. Running or carrying heavy loads multiplies your breathing rate and your smoke intake.
• Keep your car windows up and set the AC to recirculate before you get in.
• Once back inside, remove and bag your outer clothing immediately. Shower and wash your hair before sitting on furniture.

Step 5 — After the Fire: Decontamination Protocol

The fire is out. The air looks clearer. This is when people relax too soon — and it's a mistake. Wildfire ash contains heavy metals, burned plastics, asbestos from older structures, and concentrated PM2.5. Every surface that was exposed to smoke is contaminated.

Wait for the official all-clear. Check AirNow or your local air quality agency. You want AQI back below 50 (Good) for at least 24 consecutive hours before resuming normal outdoor activity.

Ash and surface decontamination:

• Wear gloves, eye protection, and an N95/FFP2 mask before handling any ash — even indoors.
• Wet ash before sweeping to prevent re-suspension. Dry sweeping sends fine particles back into the air.
• HEPA vacuum all indoor surfaces — floors, furniture, countertops, window sills. Do this before opening windows.
• Wipe down hard surfaces with a damp cloth; dispose of the cloth in a sealed bag.
• Wash all soft furnishings (curtains, cushion covers, bedding) that were in the home during the smoke event.

Your car:

• Clean the cabin air filter — it will be loaded with PM2.5 and ash particles.
• Wipe down all interior surfaces with a damp cloth.
• If the car was parked outside during heavy ash fall, wash the exterior before driving, so ash doesn't re-enter through the ventilation system.

Your clothing:

• Wash smoke-exposed clothing separately from other laundry.
• Run an extra rinse cycle.
• Dry indoors (not on an outdoor line) until outdoor air quality is confirmed safe.

When is outdoor air safe again?

AQI below 50 for 24+ hours is the benchmark. But also check: no visible haze, no smoke smell, and no active fire within 50 miles. If you're in a sensitive group, wait for 48 hours of Good AQI before resuming outdoor exercise.

Vulnerable Groups: Extra Precautions

Standard AQI thresholds are calibrated for healthy adults. For vulnerable groups, apply a one-category-stricter rule — meaning what's "Unhealthy for Sensitive Groups" (AQI 101–150) should be treated as "Unhealthy" (AQI 151–200) for them.

Children (under 18):

• Lungs are still developing. Even moderate smoke exposure can cause measurable airway inflammation.
• Keep children indoors when AQI exceeds 100.
• No outdoor sports, recess, or play when AQI is above 100.
• Children's masks must fit — an adult N95 on a child's face provides almost no protection.

Elderly (65+):

• Higher baseline risk of cardiovascular and respiratory events triggered by PM2.5.
• Shelter in place at AQI > 100; consider evacuation to a clean-air location at AQI > 150.

Asthma and COPD:

• Have your rescue inhaler within reach at all times during a smoke event.
• Follow your written asthma action plan. If you don't have one, contact your doctor now — before wildfire season peaks.
• Symptoms (wheezing, chest tightness, shortness of breath) can appear at AQI as low as 50 in people with severe asthma.

Pregnant women:

• Smoke exposure is linked to preterm birth and low birth weight. Treat any AQI above 100 as a shelter-in-place trigger.
• Discuss a wildfire action plan with your OB/GYN before the summer season.

People with heart disease:

• PM2.5 enters the bloodstream and can trigger cardiac events. Take protection from wildfire smoke as seriously as a person with severe asthma would.
• Limit outdoor exposure at AQI > 100; avoid all outdoor activity at AQI > 150.

Building a Wildfire Preparedness Kit

The worst time to figure out what you need is when the sky is turning orange. Assemble this kit now and store it somewhere accessible.

Respiratory protection:

• At least 2 N95 or FFP2 respirators per person (minimum standard)
• At least 1 P100 or FFP3 respirator per person (preferred for heavy smoke)
• Spare filters if using a reusable half-face respirator
• Child-sized respirators if you have children

Indoor air quality:

• Portable HEPA air purifier (sized for your main living area)
• Spare HEPA filter for the purifier
• MERV-13 furnace filters (for DIY box fan filter)
• Sealing tape and draft stoppers

Go-bag (if evacuation becomes necessary):

• Medications (7-day supply minimum), including inhalers
• Copies of important documents in a waterproof bag
• Water (1 gallon per person per day, 3-day minimum)
• Phone charger and battery pack
• Cash
• N95 masks for every household member
• Change of clothes in a sealed bag
• Pet supplies (carrier, food, medications)

Information:

• AirNow, PurpleAir, or IQAir app installed and alerts configured
• Local emergency alert system registered (Wireless Emergency Alerts in the U.S.; FR-Alert in France)
• Know your two evacuation routes before you need them

FAQ

How do I know when it's safe to go outside after a wildfire?

Wait for AQI to drop below 50 (Good) for at least 24 consecutive hours — not just a single reading. Also confirm: no visible haze, no smoke smell, and no active fire burning within 50 miles of your location. For sensitive groups (children, elderly, asthma/COPD, pregnant), extend that to 48 hours of Good AQI before resuming outdoor exercise.

Can an N95 protect me from wildfire smoke?

Yes — a properly fitted, NIOSH-approved N95 filters at least 95% of airborne particles, including the fine PM2.5 that dominates wildfire smoke. The key word is "properly fitted." If it leaks around the edges, you're not getting 95% filtration. For prolonged exposure or AQI above 200, step up to P100 or FFP3 (99.97% filtration). Cloth masks, surgical masks, and bandanas do not provide meaningful protection against wildfire smoke.

How long can I wear a mask in smoke?

An N95 or FFP2 can be worn for several hours before filtration efficiency degrades — but physical discomfort and breathing resistance are the practical limits. In heavy smoke (AQI > 200), keep outdoor time under 10 minutes regardless of mask quality. Replace your mask if it becomes visibly dirty, damp, or hard to breathe through. Reusable half-face respirators with replaceable P100/FFP3 cartridges give you longer effective wear time than disposable masks.

What AQI is dangerous?

AQI 151 is the threshold where the air is officially "Unhealthy" for everyone — not just sensitive groups. At this level, even healthy adults should limit outdoor time and wear a respirator if they go out. AQI 201 (Very Unhealthy) means avoid all outdoor activity. AQI 301+ (Hazardous) is a public health emergency — the air is actively harmful with short-term exposure. For sensitive groups, the danger threshold starts lower: AQI 101 triggers action.

Should I run my AC during a wildfire?

Yes — but only in recirculate mode, not "fresh air" intake. Recirculate mode keeps the AC running on indoor air, so you stay cool without pulling smoke-laden outdoor air inside. If your system doesn't have a recirculate option, turn it off and use a portable HEPA air purifier instead. Running AC on fresh-air intake during a wildfire air quality alert can make indoor air quality worse than outdoor air within an hour.

Useful Sources

• EPA AirNow — Wildfires — official U.S. fire and smoke map, AQI data, and public guidance
• EPA AirNow Fire & Smoke Map — real-time interactive map of active fires and smoke AQI
• CDC — Wildfire Safety Guidelines — CDC health guidance for during and after wildfires
• CDC NIOSH — Protecting Workers and the Public from Wildfire Smoke (2025) — respirator and exposure guidance
• Copernicus CAMS — Global Fire Monitoring — European satellite smoke tracking
• WHO — Wildfires and Health — WHO fact sheet on wildfire smoke health impacts
• WHO — Global Air Quality Guidelines — PM2.5 and air quality guideline values