Air Quality in Washington, Washington, D.C. — Live
Live readings from PurpleAir sensors across Washington — with free alerts the moment smoke drifts in.
AQI 43 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Washington, Washington, D.C. is AQI 43 — Good and falling — with PM2.5 at 7.8 µg/m³, the median of 5 live PurpleAir sensors reading 37 to 78. Canairy's verdict: Breathe easy.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Washington: weeds pollen is the strongest of the three at a high level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Washington and Arlington, Alexandria, Bethesda, Silver Spring. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Washington
The sensors Canairy reads in Washington are 41 AQI points apart right now, from Good to Moderate, which is the whole reason one city-wide number can mislead you: the median describes air you may not be standing in.
| From city center | AQI | Category |
|---|---|---|
| 1.9 mi ENE | 48 | Good |
| 2.6 mi WSW | 37 | Good |
| 3.1 mi ENE | 38 | Good |
| 4.8 mi NNW | 51 | Moderate |
| 6.6 mi NE | 78 | Moderate |
For most of the year Washington's air is ordinary big-city air, shaped by Beltway traffic and the humid Mid-Atlantic summer. The days people remember are the smoke days: in June 2023, Canadian wildfire smoke pushed the District to Code Purple and its air to a peak of 273 on the AQI scale, and the pattern returned in July 2026. The quieter, more regular problem is summer ozone, which the region violates most years.
What Canairy does for Washington
A clear verdict
Not just a number — a plain-English call for Washington: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Washington or across the country, on one screen.
What the air in Washington is doing next
| When | AQI | Expected air quality | Main pollutant |
|---|---|---|---|
| Today | 43 | Good | ozone |
| Tomorrow | 45 | Good | ozone |
| Monday | 48 | Good | ozone |
| Tuesday | 51 | Moderate | ozone |
| Wednesday | 54 | Moderate | ozone |
Forecast from EPA AirNow for the Northern Virginia and DC reporting area. Canairy watches the live sensors against it and tells you when the air actually crosses your threshold, rather than leaving you to check.
The smoke days people still talk about
On June 8, 2023, smoke from more than a hundred Canadian wildfires settled over the region and the District went to Code Purple, the level where air is very unhealthy for everyone, not just people with asthma or heart conditions. DC Public Schools canceled outdoor activities, the city opened 24-hour shelters for people without housing, and the air peaked at an AQI of 273. For a few days the Washington Monument was a gray silhouette and the sun turned orange.
That kind of event is no longer a once-in-a-lifetime thing. In July 2026 the Metropolitan Washington Council of Governments issued another Code Purple for DC and Baltimore as Canadian smoke rolled in on top of low-to-mid-90s heat. Wildfire smoke arrives with little warning and can lift just as fast, which is exactly the situation where checking a live sensor near you beats guessing from how the sky looks.
The everyday problem is summer ozone, not smoke
Most of Washington's bad-air days have nothing to do with fires. Ground-level ozone is the number one air quality problem across the Baltimore-Washington region, and it is the one federal pollutant the area still routinely violates. It forms when pollution from traffic, power plants and solvents cooks in sunlight, so it builds through hot, humid, stagnant afternoons and peaks later in the day, right through the May-to-September stretch when people most want to be outside.
The American Lung Association's 2025 State of the Air gave the Washington metro an F for ozone, ranking it among the worst 40 metros in the country, and dropped its daily particle-pollution grade from a C to an F after the 2023 smoke year. On a Code Orange ozone day the air is unhealthy for sensitive groups, meaning kids, older adults, and anyone with asthma or heart trouble, even when the sky looks perfectly clear.
The long trend is actually up
It is easy to feel like the air keeps getting worse, but the longer arc points the other way. In the 1980s and 90s the region averaged around 30 Code Orange days or worse every year. Today it is closer to four or five, a change local experts credit to public transit, more efficient vehicles and cleaner power.
That progress is real, and it also explains why the smoke years feel so jarring: they interrupt an otherwise improving picture. Traffic on the Beltway and the region's highways still drives the ozone and fine-particle pollution that shows up on the average summer day, which is why the reading near your own block can differ from the regional forecast. Watching the sensor closest to you is the simplest way to know what you are actually breathing.
Washington air quality FAQ
What is the air quality in Washington right now?
As of September 5, 2026 at 3:50 PM EDT, the air quality in Washington, Washington, D.C. is AQI 43 — Good — with PM2.5 at 7.8 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
When is air quality worst in Washington, DC?
Two seasons matter. Ground-level ozone is the region's most persistent problem and builds on hot, humid, stagnant afternoons from roughly May through September, producing Code Orange days when the air is unhealthy for sensitive groups even under a clear sky. On top of that, Canadian wildfire smoke has pushed the city to Code Purple in June 2023 and again in July 2026, which is a much sharper spike that can arrive and clear within a day or two.
How bad did the 2023 wildfire smoke get in Washington, DC?
On June 8, 2023, Canadian wildfire smoke drove the District to a Code Purple alert, the level where the air is very unhealthy for everyone. The AQI peaked around 273, DC Public Schools canceled outdoor activities, and the city opened 24-hour shelters for people without housing. It was among the worst air quality on record for the area, and a similar Code Purple event returned in July 2026.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 5 curated PurpleAir sensors Canairy tracks in and around Washington, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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Air quality near Washington
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