Air Quality in Philadelphia, Pennsylvania — Live
Live readings from PurpleAir sensors across Philadelphia — with free alerts the moment smoke drifts in.
AQI 11 from 3 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Philadelphia, Pennsylvania is AQI 11 — Good and falling — with PM2.5 at 1.9 µg/m³, the median of 3 live PurpleAir sensors reading 10 to 17. 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 Philadelphia: weeds pollen is the strongest of the three at a very low 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 Philadelphia and Camden, Cherry Hill, Upper Darby, Bensalem. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Philadelphia
The sensors Canairy reads in Philadelphia agree right now — all 3 sit in the Good band, a 7-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 2.7 mi NE | 17 | Good |
| 3.1 mi WSW | 11 | Good |
| 4.7 mi N | 10 | Good |
Philadelphia's air is shaped by two very different problems: summer smog cooked up over the Delaware Valley's highways and heat, and the wildfire smoke that now drifts down from Canada, most memorably in June 2023 when the skyline vanished behind a hazardous orange haze. The American Lung Association gives the city failing grades for both ozone and daily particle pollution, so the air here is worth watching even on days the sky looks clear.
What Canairy does for Philadelphia
A clear verdict
Not just a number — a plain-English call for Philadelphia: 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 Philadelphia or across the country, on one screen.
The June 2023 smoke turned the sky orange and postponed a Phillies game
On June 7, 2023, smoke from Canadian wildfires settled over the Delaware Valley and pushed Philadelphia's air quality into some of the worst readings any US city saw that year. Morning AQI numbers climbed past 200, into the purple range, and by early Thursday the region logged spikes of 350 and higher, firmly in the hazardous category. Pennsylvania's Department of Environmental Protection declared a statewide Code Red, warning that the air was unhealthy for everyone, not just sensitive groups.
The haze was thick enough to be visible from block to block, and the disruption was real: the Phillies postponed their game against the Detroit Tigers because the air was unsafe to play in. Smoke like this has no local source you can point to, which is exactly why it catches people off guard. It arrives with the wind, and the only way to know it is happening is to watch the numbers, which is what Canairy does for the places you save.
Summer heat and highway traffic cook up ozone all season
Even without wildfire smoke, Philadelphia struggles with ground-level ozone, the invisible pollutant that makes up summer smog. It forms when sunlight and heat bake the exhaust from cars, trucks, and industry, and the Delaware Valley has plenty of all three. On-road vehicles produce close to 40 percent of the nitrogen oxides emitted inside city limits, and the commuter corridors along I-95 and I-76 act as long ribbons of pollution feeding the reaction.
The result is that the greater Philadelphia region fails to meet the federal ozone standard on roughly 20 days a year, almost all of them between May and September when the heat is strongest. The city sits in EPA nonattainment for ozone, and the American Lung Association's 2025 report handed Philadelphia failing grades for both high-ozone days and daily particle spikes. Hot, still summer afternoons are when ozone peaks, which is often when people most want to be outside.
A refinery legacy that ended in a 2019 explosion
For decades South Philadelphia lived next to the largest oil refinery on the East Coast, the Philadelphia Energy Solutions complex, which processed around 335,000 barrels of crude a day. On June 21, 2019, a corroded pipe failed and touched off a series of explosions, releasing hydrocarbons and hydrofluoric acid and throwing a vessel fragment across the Schuylkill River. The refinery shut down for good five days later, on June 26, ending more than a century of oil processing on the site.
The closure removed a major fixed source of pollution from the city's air, but the broader industrial and port activity across the surrounding counties has not gone away, and neither has the diesel traffic that moves goods through the region. That mix is part of why the Philadelphia-Reading-Camden area still ranks among the more polluted metros in the Mid-Atlantic. Neighborhood-level readings can differ a lot from the citywide average, which is why a sensor near your own block tells you more than a regional headline.
Philadelphia air quality FAQ
What is the air quality in Philadelphia right now?
As of October 20, 2026 at 11:27 PM EDT, the air quality in Philadelphia, Pennsylvania is AQI 11 — Good — with PM2.5 at 1.9 µg/m³, the median of 3 live PurpleAir sensors. Open the windows. Great for outdoor activity.
When is Philadelphia's air quality usually worst?
Two seasons matter most. Summer, roughly May through September, is ozone season, when heat and sunlight bake traffic and industrial pollution into smog and the region breaks the federal ozone standard on about 20 days a year. Separately, wildfire smoke from Canada can arrive at almost any point in the warm months, as it did dramatically in June 2023, when Philadelphia's AQI reached the hazardous range and a Phillies game was postponed.
Did closing the South Philadelphia refinery clean up the air?
The Philadelphia Energy Solutions refinery, the largest on the East Coast, shut down in June 2019 after an explosion, which removed a major fixed pollution source from the city. But traffic, diesel trucks, port activity, and ozone-forming emissions across the region remain, and the Philadelphia area still earns failing grades for ozone and daily particle pollution in the American Lung Association's reports. A local sensor is the best way to know your own block's air on a given day.
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 3 curated PurpleAir sensors Canairy tracks in and around Philadelphia, 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 Philadelphia
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