Wildfire smoke and your health
The sky turns that flat orange-gray, the air smells like a campfire that won't go out, and your eyes start to sting. If you're searching what is causing the bad air quality today, wildfire smoke is very often the answer — even when the nearest fire is hundreds of miles away.
It matters because the smoke isn't just an irritant. Its main hazard is a fine particle small enough to reach deep into your lungs, and it hits some people — those with asthma, heart disease, the very young and very old — harder than others.
This page relays what the US Environmental Protection Agency (EPA) says about wildfire smoke and your health: what it is, who is most at risk, and the concrete steps the EPA recommends to reduce your exposure. Every health statement below is attributed to the agency, with a link.
What wildfire smoke actually is
According to the EPA, wildfire smoke is a mixture of gases and fine particles from burning trees, brush, and other material. Of everything in that mixture, the EPA says the main health concern is fine particulate matter, or PM2.5 — particles so small they can travel deep into the lungs and even into the bloodstream.
That size is the whole problem. Bigger particles get caught in your nose and throat; PM2.5 slips past those defenses. Per the EPA, that's why smoke can affect you well beyond a little coughing, and why the protective steps further down all aim at one thing — breathing in less of it.
Who is most at risk
Smoke can bother anyone, but the EPA identifies groups who are more likely to be affected and should take extra care when air quality is poor. Per the EPA, these sensitive groups include:
- People with heart or lung disease, including asthma and COPD
- Older adults
- Children and teens
- Pregnant people
If you or someone in your household is in one of these groups, the EPA advises watching air quality more closely and reducing exposure sooner. This is the same guidance the EPA gives publicly — it isn't medical advice tailored to you.
Symptoms wildfire smoke can cause
The EPA lists common symptoms of smoke exposure: burning eyes, a runny nose, coughing, wheezing, and shortness of breath. For most healthy people these are uncomfortable but temporary.
Per the EPA, smoke can also trigger asthma attacks, and for people with heart or lung conditions it can lead to more serious effects. If you notice symptoms that are severe or that don't ease when you get to cleaner air, the EPA advises seeking medical help — and remember this page relays general guidance, not a diagnosis.
Asthma and air quality today: what the EPA says to do
If you have asthma and you're checking the asthma air quality today, the EPA's framing is straightforward: smoke can set off attacks, so the goal is to stay ahead of it. Per the EPA, people with heart or lung disease — asthma included — should follow the plan their doctor gave them and keep their medicines on hand.
In practice that means having your asthma action plan and quick-relief medicine ready before a smoky day, and reducing your exposure using the steps below. We deliberately don't tell you which medicine to take or how much — that's your clinician's call, and it's exactly what your action plan already spells out. This is general agency guidance, not medical advice.
What the EPA recommends when it's smoky
When smoke is in the air, the EPA's advice centers on one idea: reduce how much smoke you breathe. Here are the protective actions the EPA gives, relayed as-is.
- Check your local AQI. Use the Air Quality Index at AirNow to see how bad the air is where you are before deciding what to do.
- Stay indoors with windows and doors closed when it's smoky, to keep outdoor particles out.
- Run a portable HEPA air purifier, or a DIY Corsi-Rosenthal box, to lower indoor particle levels.
- Make a “clean room” — one room you can keep as smoke-free as possible with the air cleaner running.
- Avoid adding indoor pollution: the EPA says not to burn candles, fry food, vacuum, or smoke while it's smoky, as these add particles.
- Limit strenuous outdoor activity so you breathe in less smoke.
- People with heart or lung disease should follow the plan their doctor gave them and keep their medicines on hand.
Sources: EPA, “Wildfire Smoke and Your Health” and EPA, “Wildfire Smoke: A Guide for Public Health Officials.” AQI via AirNow.
Do masks help against wildfire smoke?
Some do. Per the EPA, a well-fitted N95 or P100 respirator can reduce how much fine particulate you breathe in. The fit is the point — a respirator only helps if it seals to your face.
Just as important, the EPA is explicit that cloth and surgical masks do not protect against fine particles. They may catch larger droplets, but they don't stop PM2.5. If a mask is your plan for a smoky day, the EPA's guidance points to a properly fitted N95 or P100, not a cloth face covering.
Why the air is bad today even with no fire nearby
If you're wondering what is causing the bad air quality today and there's no visible fire, wildfire smoke is a common culprit. Smoke can travel hundreds of miles on the wind and spike PM2.5 far from the flames — which is why a hazy, smoky day can arrive in a city with no fire for states around it.
Because it's so localized and shifts by the hour, the only way to know your air is to check where you are. See where the smoke is on the wildfire smoke map, and check the particulate and AQI for your location on the air quality map. To plan ahead — whether the smoke is forecast to clear or linger — see the smoke forecast. For the fires producing the smoke and the broader picture, see US wildfire statistics.
Wildfire smoke and health FAQ
- What is causing the bad air quality today?
- Often it's wildfire smoke. The EPA describes wildfire smoke as a mix of gases and fine particles, with PM2.5 as the main health concern. That smoke can drift hundreds of miles, so your air can be bad with no fire nearby. Check the air quality map and smoke map to confirm what's happening where you are.
- Is wildfire smoke bad for your health?
- Per the EPA, yes — the fine particulate (PM2.5) in smoke can get deep into the lungs and bloodstream, and can cause burning eyes, runny nose, cough, wheezing, and shortness of breath. It can trigger asthma attacks and cause more serious effects in people with heart or lung conditions. This is general information, not medical advice.
- Who is most affected by wildfire smoke?
- The EPA lists sensitive groups: people with heart or lung disease (including asthma and COPD), older adults, children and teens, and pregnant people. If that's you or your household, the EPA advises watching air quality closely and reducing exposure sooner.
- What should I do if I have asthma and the air quality is bad today?
- The EPA's general guidance for people with heart or lung disease, asthma included, is to follow the plan your doctor gave you and keep your medicines on hand — and to reduce your exposure to smoke. We don't advise which medicine to take or how much; that's in your asthma action plan and is your clinician's decision.
- Do N95 masks protect against wildfire smoke?
- Per the EPA, a well-fitted N95 or P100 respirator can reduce how much fine particulate you breathe. Cloth and surgical masks do not protect against fine particles. Fit matters — a respirator only helps if it seals to your face.
- How can I clean the air inside my home during wildfire smoke?
- The EPA recommends staying indoors with windows and doors closed, running a portable HEPA air cleaner or a DIY box-fan filter, and setting up a “clean room.” It also advises against adding indoor pollution — no candles, frying, vacuuming, or smoking while it's smoky.
Sources & method
Every health statement on this page is relayed from the US EPA. What wildfire smoke is, that PM2.5 is the main health concern, the sensitive groups, the symptoms, the asthma framing, the mask guidance, and the protective actions all come from the EPA's “Wildfire Smoke and Your Health” and its “Wildfire Smoke: A Guide for Public Health Officials” course; check your local Air Quality Index at AirNow. This is general information from public-health agencies, not medical advice — for your own situation, talk to your clinician. No spread predictions, no risk editorializing, no evacuation guidance — we relay agency information only, attributed. Reviewed by Marko Visic, MPharm, BSc Physics.