What to do when bushfire smoke arrives

How bad bushfire smoke actually is

Bushfire smoke is PM2.5-rich and toxic. Long-term exposure does damage comparable to years of cigarette smoking. Even healthy people get coughs, sore eyes, and headaches. For asthmatics, COPD sufferers, pregnant women, kids, and elderly, smoke is a medical event.

Step 1: Seal the house

1. Close every door and window.
2. Switch your AC to recirculate. Look for the curved-arrow button. Outside-air vents will pull smoke straight in.
3. Block obvious gaps with damp towels: under doors, around old window frames.
4. Run an air purifier in your main living room and bedroom.

Step 2: Build a clean room

Pick one room (usually the bedroom). Close it off. Run a HEPA purifier sized for the room. The CDC and EPA both recommend this as the single most effective home strategy during a prolonged smoke event. AQI in the clean room can be 80% lower than the rest of the house.

Step 3: If you have to go outside

• N95 or P2 mask, properly fitted. Cloth and surgical masks don't filter PM2.5.
• Wraparound sunglasses to protect eyes from irritation.
• Cut your time outside. An hour at AQI 200 is roughly equivalent to smoking eight cigarettes.
• No outdoor exercise. Treadmill, rest day, or postpone.

Step 4: Watch yourself

Warning signs to act on:

• A cough that doesn't go away in a few hours
• Tight chest or wheezing
• Confusion, dizziness, or unusual fatigue
• Asthma medication wearing off faster than usual

These mean fresh air, medical advice, or both. Don't tough it out.

Step 5: After the smoke clears

Once AQI drops below 50, open the windows and air the house out. Replace HVAC filters. Wipe down hard surfaces. Don't vacuum aggressively for a week. That stirs up settled particles. A robot vacuum on low or a damp mop is gentler.

Why bushfire smoke is so dangerous to breathe

Bushfire smoke is dominated by fine particulate matter known as PM2.5, particles small enough to travel deep into the lungs and even pass into the bloodstream. They aggravate asthma and heart conditions, irritate the eyes and throat, and on heavy smoke days the air quality index can climb into the hazardous range many times higher than a normal city day. The danger is not just for people with existing conditions; sustained exposure affects everyone, which is why smoke events deserve a deliberate response rather than just toughing it out.

Sealing the house when smoke arrives

When smoke rolls in, the instinct to open a window for "fresh air" is exactly wrong. Close all windows and doors, shut any vents or chimney dampers you can, and if you have air conditioning, switch it to recirculate so it is not drawing smoky air inside. Creating a sealed indoor space with cleaner air is your best protection. A HEPA air purifier running in the room where you spend the most time, usually the bedroom, makes a real measurable difference to indoor particle levels during a smoke event. Sizing it to the room and running it continuously is what counts.

When you have to go outside

If you must go out in heavy smoke, an ordinary cloth or surgical mask does little against fine particles. A properly fitted P2 or N95 respirator is what actually filters PM2.5, and only if it seals against your face. Keep outdoor time short, avoid exertion that makes you breathe hard, and get back to clean indoor air as soon as you can. Watch the official air quality index rather than judging by how the smoke looks, because the haze can thin while particle levels stay high. People with asthma, heart conditions, the very young, the elderly, and pregnant women should be especially cautious and keep medication close.

Frequently asked questions

Should I open windows during bushfire smoke?

No. Keep windows and doors shut to keep smoke out, set air conditioning to recirculate, and run a HEPA purifier indoors. Only air the house once the air quality index has come back down.

Do face masks help against smoke?

Only a properly fitted P2 or N95 respirator filters the fine particles in smoke, and only if it seals to your face. Cloth and surgical masks do very little against PM2.5.

How do I know when it is safe to open up again?

Watch the official air quality index, not the visible haze. Once readings return to the good or moderate range, open the windows and flush the stale indoor air with a cross-breeze.

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