Wildfire Smoke and Haze: Health Risks, AQI and Protection

At a glance

What matters most

01
Wildfire smoke commonly raises PM2.5, which can travel far beyond the fire itself and create unhealthy haze.
02
Smoke conditions can shift rapidly, so current local alerts and air-quality information take priority over a fixed schedule.
03
A clean-air room, correctly sized portable air cleaner and reduced indoor particle sources can lower exposure indoors.
04
A properly fitting N95 or similar particle-filtering respirator can reduce particle exposure outdoors, but it does not replace evacuation orders or protect against every hazard.

Why smoke and haze need a different response

Wildfire smoke is a mixture of gases and particles. Fine particles, including PM2.5, are a major health concern because they can remain airborne and travel long distances. Haze can arrive far from a visible fire, and outdoor conditions can change with wind, fire behaviour and weather.

Check current local air-quality information, smoke forecasts and official emergency messages before making plans. If officials issue an evacuation order, shelter instruction or health advisory, that instruction takes priority over general AQI guidance.

Create cleaner indoor air

Step	Why it helps
Close windows and doors when smoke is high	Reduces unnecessary entry of smoky outdoor air.
Use recirculate mode where appropriate	Can reduce the outdoor air drawn into a vehicle or compatible HVAC system.
Run a correctly sized portable air cleaner	Helps reduce airborne particles in the room where people spend time.
Make one room a clean-air room	Creates a lower-particle space when the whole building cannot be kept equally clean.
Avoid indoor particle sources	Skip smoking, candles, incense, frying, vacuuming and other activities that add particles.

If you must go outside

Choose a time when local conditions are better, if one is available, and keep the trip as short as possible.
Reduce physical intensity, take breaks in cleaner air and avoid strenuous outdoor exercise.
Keep vehicle windows closed and use recirculate mode when appropriate.
For particle-heavy smoke, consider a genuine, well-fitting NIOSH-approved N95 or similar particle-filtering respirator; facial-hair gaps and poor fit reduce protection.
Do not use a respirator as a reason to remain in an evacuation area or ignore official instructions.

Who may need to act earlier

Children, older adults, pregnant people, people with heart or lung disease, people with asthma and outdoor workers can face greater risk or exposure during smoke events. People with a health condition should follow their clinician’s action plan and contact a healthcare professional if symptoms worsen.

Seek urgent medical help for severe breathing difficulty, chest pain, blue or grey lips or face, confusion, fainting or other emergency symptoms. For everyone, local public-health instructions are the most relevant source during an active smoke event.

Frequently asked questions

Should I stay indoors when it is smoky outside?

Usually, staying in cleaner indoor air and reducing time outdoors lowers smoke exposure unless officials advise evacuation or another action. Indoor air can still be affected, so close openings when appropriate, use filtration and avoid adding indoor particles.

Does a HEPA air purifier help with wildfire smoke?

A properly sized portable particle air cleaner can reduce airborne particles in the room where it runs. Its effectiveness depends on room size, airflow, placement, filter condition and controlling smoke entry and indoor sources.

Can an N95 protect me from wildfire smoke?

A genuine, well-fitting N95 can reduce exposure to smoke particles. It does not remove every gas, is less effective with gaps around the face and does not replace evacuation orders, cleaner indoor air or medical care when needed.

Primary sources

This reference was prepared from the following primary public-health and regulatory sources:

Wildfire Smoke and Haze: How to Reduce Your Exposure