IAQng public signal
How many cigarettes is today's air?
Today's outdoor air, translated into something everyone understands: cigarettes. See how much smoke you're breathing where you live.
≈ -- cigarettes today
About 22 µg/m³ of PM2.5 over a day ≈ one cigarette.
The national picture
Click the map to highlight any city.
Loading the national smoke map…
Outside is only half the story
Smoke crosses borders, but buildings decide how much people actually breathe. Filtration, ventilation, and how a space is run can change indoor exposure dramatically. Two buildings on the same street can have very different air.
What helps indoors when the air is like today's
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Filters do the real work. When the outdoor number climbs, indoor filtration is what stands between you and it. Run the HVAC fan continuously, step up to a higher-MERV filter, and don't stretch the change interval on smoky days.
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Keep the outside air out. Close windows and hold off on fresh-air intake while levels are high. Bring it in during the cleaner hours instead.
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Make one clean room. A portable HEPA purifier sized to the room can keep a single space well below the number outside.
For everyone
Know your air. Follow the mission.
IAQng is a public-awareness project: this map, and a manifesto for treating indoor air like it matters. Join the list and we'll send the signal and what's next.
For facility managers
Bring the number indoors.
This map is the outdoor number. SpaceBot is our platform for the indoor one: it monitors what people actually breathe inside a building and shows how filtration, ventilation, and daily operations change it.
How it works
Wildfire smoke is mostly PM2.5, the fine particles air monitors already track nationwide (along with traffic and dust). Berkeley Earth's rule of thumb turns it into cigarettes: 22 µg/m³ over a day ≈ one. It's a public-awareness illustration, not a medical or regulatory measurement.
Where the data comes from
EPA AirNow, the federal air-quality network. Every hour we pull every PM2.5 station reporting in the continental US, about 1,200 on a typical day. AirNow publishes quickly rather than perfectly: these are preliminary readings, not the regulatory record, and they can be revised later.
How often it updates
Hourly. We read the hour that closed two hours ago, since that is roughly how long stations take to report, and keep a rolling 24 hours of it. The timestamp on the map is the data's, not your browser's.
How the number is worked out
Each station reports fine particles in micrograms per cubic metre. We average its last 24 hours and divide by 22. “Right now” skips the average and shows the latest hour instead, expressed as the pace it would set over a full day.
How reliable it is
Stations are points; the map is a surface. Any spot between them is an inverse-square distance-weighted blend of the stations around it, so a station twice as far away counts a quarter as much. Next to a station you are seeing a measurement. In the rural West you may be seeing an interpolation across a hundred miles. Spots with no station in range are left unpainted.
What it isn't
PM2.5 is every fine particle, not just smoke: traffic, dust and industry are in every reading. The cigarette figure compares particle mass only. A real cigarette also delivers nicotine, carbon monoxide and dozens of carcinogens straight to the lungs. And this is outdoor air at ground level; what you breathe inside depends on the building.
Air-quality data: U.S. EPA AirNow (preliminary, not regulatory). Map outline: U.S. Census cartographic boundaries (public domain). Cigarette equivalence: Berkeley Earth. Refreshed hourly by SpaceBot for IAQng.