How to protect yourself from wildfire smoke, monitor air quality, and reduce health risks during a wildfire event.
Wildfire smoke is one of the most widespread and underestimated hazards during a fire event. It can travel hundreds of miles from the source, turning clear skies hazy and pushing dangerous particulate matter into communities far from any visible flame. Understanding how to read air quality data, protect your lungs, and make informed decisions about shelter and evacuation can be the difference between a manageable inconvenience and a serious health crisis.
Wildfire smoke is a complex mixture of gases and fine particles produced when wood and other organic matter burn. The particles of greatest concern are PM2.5 — particulate matter smaller than 2.5 micrometres in diameter. These particles are so small they can bypass your nose and throat and lodge deep in your lungs, causing inflammation and triggering respiratory and cardiovascular problems.
Beyond particles, smoke contains:
Even healthy adults can experience irritation, but vulnerable populations — children, the elderly, pregnant women, and those with asthma or heart disease — face significantly greater risk.
The Air Quality Index (AQI) is the standard scale used by governments worldwide to communicate daily air quality. During wildfires, tracking the AQI for your area should become a daily habit.
| AQI Value | Category | Colour | Health Guidance |
|---|---|---|---|
| 0–50 | Good | Green | Air quality is satisfactory |
| 51–100 | Moderate | Yellow | Sensitive individuals should limit prolonged outdoor exertion |
| 101–150 | Unhealthy for Sensitive Groups | Orange | Children, elderly, and those with conditions should reduce time outdoors |
| 151–200 | Unhealthy | Red | Everyone may begin to experience health effects |
| 201–300 | Very Unhealthy | Purple | Health alert — everyone should avoid prolonged outdoor activity |
| 301–500 | Hazardous | Maroon | Emergency conditions — remain indoors |
⚠️ During active wildfires, AQI values can spike rapidly from Moderate to Hazardous within a few hours. Do not rely on yesterday's forecast. Check the AQI every morning and whenever smoke becomes visible or you smell it.
Multiple tools are available to track air quality in real time:
When monitoring, note that official government stations average readings over time and may lag behind rapidly changing conditions. PurpleAir sensors update more frequently but can read slightly higher due to differences in calibration. Use multiple sources.
When smoke is heavy outside, the goal is to maintain a cleaner air environment inside. A typical home will allow outdoor air to infiltrate naturally, so you need to actively create a cleaner refuge.
| Home Type | Natural Air Changes per Hour | Smoke Protection Level |
|---|---|---|
| Very tight (modern sealed construction) | 0.25–0.5 | High — effective shelter in place |
| Average suburban home | 0.5–1.0 | Moderate — supplement with HEPA purifier |
| Older, draughty home | 1.0–3.0 | Low — HEPA purifier essential, consider evacuation |
| Tent or temporary structure | 3.0+ | Minimal — not suitable for smoke protection |
When you must go outside during a smoke event, the right mask matters.
N95 respirators (or equivalent P2 in Australia/P100 in Europe) filter at least 95% of airborne particles when properly fitted. These are the minimum standard for wildfire smoke protection.
What does NOT protect you:
⚠️ N95 masks do not work well for people with beards. Facial hair prevents a proper seal. In this case, consider a powered air-purifying respirator (PAPR) or use a HEPA-filtered enclosed space.
Children breathe more air relative to their body weight than adults and spend more time outdoors. During AQI levels above 150, keep children inside. Cancel outdoor sports and activities. Schools should move activities indoors and use HEPA purifiers in classrooms.
Smoke exposure is linked to increased risk of preterm birth, low birth weight, and other complications. Follow the same guidance as other sensitive groups but be even more conservative — stay indoors whenever AQI exceeds 100.
Have your rescue inhaler accessible at all times. Know your personal action plan. If your symptoms worsen despite staying indoors, contact a healthcare provider — do not wait.
Pets are also affected by wildfire smoke. Limit their outdoor time, especially exercise, during smoke events. Watch for excessive coughing, eye discharge, or breathing difficulties.
Smoke alone does not always mean evacuation is necessary. However, consider evacuating if:
Always obey official evacuation orders. No air quality concern is worth staying in a mandatory evacuation zone.
Once the wildfire passes and air quality returns to Good or Moderate levels:
| Situation | Action |
|---|---|
| AQI 0–100 | Normal activities, sensitive groups take caution |
| AQI 101–150 | Sensitive groups stay indoors; others limit exertion |
| AQI 151–200 | Everyone stay indoors; run HEPA purifier |
| AQI 201–300 | Stay indoors; seal gaps; N95 if must go out |
| AQI 301+ | Hazardous — evacuate if possible or seal clean room |
| Outdoors required | Wear properly fitted N95 or P2 respirator |
| Home not sealable | Seek public shelter with HEPA filtration |
| Symptoms worsening | Seek medical attention |
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