Should I open my windows when there is wildfire smoke?

When the air is smoky, keep windows and doors closed to keep particles out. Run your central air or a fan on recirculate. When the air quality improves, even for a few hours, open the windows and air the house out. Watching the AQI trend, not just the current number, tells you when that window opens.

Can I exercise outside during wildfire smoke?

It depends on the AQI. Up to about 100 most people are fine, though anyone with symptoms should ease off. From 101 to 150 sensitive groups should shorten and lighten hard outdoor exertion. At 151 and above, everyone should cut back on prolonged or heavy activity and move workouts indoors. The two dials to turn down are how hard you go and how long you stay out.

Is it safe to send kids to practice or recess when it is smoky?

Children breathe faster and are still developing their lungs, so they count as a sensitive group. At AQI 101 and up, shorten outdoor time and skip the hardest running. At 151 and up, move it indoors. Note that N95 respirators are not made to fit young children and will not seal on them, and children under 2 should not wear a respirator at all, so for kids the real protection is staying indoors with filtered air.

Do I need an air purifier, and what kind?

A portable air cleaner with a HEPA filter, run continuously with the doors and windows closed, noticeably lowers indoor particle levels. If you have central air, run it with a high-efficiency filter rated MERV-13 or higher and change it often. A do-it-yourself box-fan-and-filter unit works too when you cannot buy a purifier.

What is a clean room?

A clean room is one room you keep as smoke-free as possible during an event: windows and doors closed, a portable HEPA air cleaner running, and no activities that add particles such as frying, vacuuming without a HEPA vacuum, burning candles, or smoking. A bedroom is a common choice. It gives vulnerable people a place to ride out the worst air.

What about pets during wildfire smoke?

Smoke affects animals too. Bring pets indoors when the air is bad, keep walks short and calm, and give birds and other sensitive animals extra care. If a pet is coughing, struggling to breathe, or unusually tired, call your vet.

What to do when the air is bad

Q: Do masks protect against wildfire smoke?

A well-fitted N95 or P100 respirator can protect you from the fine particles in wildfire smoke. Cloth and surgical masks do not, because smoke particles slip around the edges and through the fabric. The mask only works if it seals to your face, which is why they do not work on beards or on small children.

A plain checklist for smoky days: whether to open the windows, whether the kids can go out, when to run the air cleaner, and what actually protects you. Set by the AQI, the number SmokeDar leads with.

One number runs the whole thing. Look up your town's AQI on the radar, then find that number in the levels below. Higher means more particles in the air you are breathing, so you do two things: spend less time outside, and take it easier while you are there. Everything else on this page is detail on those two moves.

Quick start

Get your number. Open SmokeDar and read the big AQI for your town. That is the observed, EPA-monitored figure when a monitor is nearby. Check Tomorrow for the forecast.
Find your level. Match the number to a card below. Green and yellow are ordinary days. Orange means sensitive people take care. Red and above means everyone does.
Take the two actions. Cut how long you are outside and how hard you work while there. Close the windows when it is smoky; open them when the air clears.
Protect the vulnerable first. Kids, older adults, pregnant people, and anyone with a heart or lung condition feel it sooner. Give them filtered indoor air and watch for symptoms.

What each AQI level means for your day

Colors and categories are the EPA's standard US Air Quality Index. The advice is drawn from AirNow's activity guidance.

GoodAQI 0–50

Air is clean. Go do whatever you were going to do.

ModerateAQI 51–100

Fine for almost everyone. If you are unusually sensitive to smoke and you notice symptoms, take it a little easier on long or hard outdoor efforts.

Watch: people who already know smoke bothers them.

Unhealthy for Sensitive GroupsAQI 101–150

Sensitive groups should shorten and lighten heavy outdoor exertion, take more breaks, and keep an eye out for coughing, a scratchy throat, or shortness of breath. Everyone else can carry on with an eye on how they feel.

Sensitive groups: children and teens, adults over 65, pregnant people, and anyone with asthma or a heart or lung condition.

UnhealthyAQI 151–200

Everyone should cut back on prolonged or heavy outdoor activity and move workouts and practices indoors. Sensitive groups should avoid it and stay inside with the windows closed and an air cleaner running.

Very UnhealthyAQI 201–300

Avoid outdoor exertion. Everyone should stay indoors as much as possible, keep windows and doors closed, and run filtration. If you have to be outside, keep it brief and wear a well-fitted N95. Sensitive groups should be in a clean room.

HazardousAQI 301+

Emergency conditions. Stay indoors with the air sealed and filtered, and keep outdoor trips to the essential. Anyone who must go out should wear a fitted N95 or P100. If breathing is hard, chest hurts, or symptoms are severe, seek medical care.

The smoky-day checklist

Do

Close windows and doors while the air is smoky, and run central air or a fan on recirculate.
Run a HEPA air cleaner continuously in the rooms you use, doors and windows shut. No purifier? A box fan taped to a MERV-13 furnace filter is a proven stand-in.
Filter your HVAC with a MERV-13 or higher filter and change it more often than usual.
Set up a clean room for anyone vulnerable: one room, sealed, air cleaner on, no smoke-making activities.
Wear a fitted N95 or P100 if you must be outside in Unhealthy air or worse. It has to seal to your face.
Shorten and soften outdoor time. Less time out, and go easier while you are there.
Bring pets indoors and keep their walks short and calm.
Air the house out when the AQI drops, even for a few hours, then close it back up if smoke returns.
Stay hydrated and keep an eye on kids, older relatives, and anyone with a lung or heart condition.

Skip

Cloth and surgical masks for smoke, the particles go right past them.
N95s on young children, they will not seal, and children under 2 should not wear one at all.
Adding indoor particles, frying, candles, incense, wood fires, smoking, and vacuuming without a HEPA vacuum all make inside air worse.
Hard outdoor workouts once the AQI is Unhealthy, the harder you breathe, the more smoke you pull in.

Common questions

Should I open my windows?

When it is smoky, keep windows and doors closed and run your air on recirculate. When the AQI improves, even for a few hours, open up and air the house out, then close it again if smoke comes back. Watching the trend, not just the current number, tells you when that window opens.

Can I exercise or run outside?

It scales with the AQI. Up to about 100 most people are fine, though anyone with symptoms should ease off. From 101 to 150, sensitive groups should shorten and lighten hard efforts. At 151 and above, everyone should cut back and move workouts indoors. Turn down two dials: how hard you go, and how long you stay out.

Can the kids go to practice or recess?

Children breathe faster and their lungs are still developing, so they are a sensitive group. At AQI 101+ shorten outdoor time and skip the hardest running; at 151+ move it indoors. N95s are not made to fit young kids and will not seal, and under-2s should not wear a respirator, so for children the real protection is filtered indoor air.

How long can I be outside?

There is no single safe number of minutes, but the idea is simple: the higher the AQI and the harder you exert, the shorter your outdoor time should be. On Unhealthy days keep trips brief and errands quick; on Very Unhealthy and Hazardous days, go out only when you must.

Do masks actually help?

A well-fitted N95 or P100 respirator does; cloth and surgical masks do not, because smoke particles slip around the edges and through the fabric. The seal is everything, which is why they do not work over a beard or on a small child.

Do I need an air purifier?

A portable HEPA air cleaner run continuously with the room closed measurably lowers indoor particles. If you have central air, run it with a MERV-13-or-higher filter and change it often. A box fan taped to a MERV-13 filter is a cheap, effective backup.

What about pets?

Smoke affects animals too. Bring them inside when the air is bad, keep walks short, and give birds and other sensitive pets extra care. Coughing, labored breathing, or unusual tiredness is a reason to call your vet.

Is this the same as what SmokeDar shows?

SmokeDar leads with the observed AQI so you can find your level here quickly. It also shows smoke aloft versus smoke at the surface, because a scary-looking sky and the air you are actually breathing are not always the same thing. Use the number for health decisions.

This guide is general information based on EPA and AirNow guidance, not medical advice. If you have asthma, a heart or lung condition, are pregnant, or care for someone vulnerable, talk to a doctor or your local health department, and treat AirNow as the official source of record.

Where this comes from

AirNow: When smoke is in the airOfficial EPA/AirNow actions to protect your health during a smoke event. AirNow: AQI basics and activity guidanceWhat each color category means and the activity recommendations behind these cards. EPA: Create a clean roomHow to set up one sealed, filtered room during wildfire smoke. EPA: Protecting children from smokeWhy kids are more at risk and why respirators do not fit them.

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