Air Quality in Allentown, Pennsylvania — Live
Live readings from PurpleAir sensors across Allentown — with free alerts when summer ozone or warehouse-corridor pollution builds.
AQI 17 from 2 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Allentown, Pennsylvania is AQI 17 — Good and falling — with PM2.5 at 3.2 µg/m³, the median of 2 live PurpleAir sensors reading 17 to 18. 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 Allentown: weeds pollen is the strongest of the three at a very 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 Allentown and Bethlehem, Easton, Emmaus, Whitehall. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Allentown
The sensors Canairy reads in Allentown agree right now — all 2 sit in the Good band, a 1-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 4.1 mi WSW | 17 | Good |
| 4.6 mi NW | 18 | Good |
Most of the year, Allentown's air is unremarkable in the best way — steady Good-to-Moderate readings that don't make the news. The exception is summer, when a heat wave settles over the Lehigh Valley and the Pennsylvania DEP calls a Code Orange ozone action day, and the valley's other defining feature — one of the busiest warehouse and freight corridors in the country along I-78 and Route 22 — adds its own share of fine particle pollution on top.
What Canairy does for Allentown
A clear verdict
Not just a number — a plain-English call for Allentown: 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 Allentown or across the country, on one screen.
Summer ozone action days are Allentown's most common air alert
Ground-level ozone forms when heat and sunlight cook vehicle and industrial exhaust, and the Lehigh Valley gets Code Orange alerts most summers when a heat wave settles in. The DEP called one for the Valley on June 3, 2025, and issued another for eastern and south-central Pennsylvania on May 18, 2026 during an early-season heat spell — both times advising anyone with asthma or heart conditions to cut back on strenuous outdoor activity.
These alerts aren't unique to Allentown — the June 2025 Code Orange stretched across Berks, Lehigh, Northampton, Dauphin, Cumberland, Lancaster, Lebanon, and York counties, because ozone is a regional pollutant that doesn't respect county lines. What varies block to block is how much extra particulate gets layered on top locally, which is why Canairy reads sensors near the specific places you've saved rather than one valley-wide average.
The valley's warehouse boom brought truck traffic — and its own air monitors
The Lehigh Valley has become one of the country's biggest inland distribution hubs, thanks to I-78, Route 22, and I-476 putting it within two hours of the ports of Newark and Wilmington. Amazon runs a 1.1-million-square-foot fulfillment center at the Chrin Commerce Centre, and projects like the Cubes at Lehigh Valley and the Cubes at Alpha have added hundreds of thousands more square feet of warehouse space — and the freight-truck traffic that comes with it.
Lehigh and Northampton counties took the concern seriously enough to fund their own answer: the Lehigh Valley Breathes project, launched in fall 2023 with about $100,000 in county money, deployed 40 PurpleAir monitors specifically to track PM2.5 from warehouse-related truck traffic, supplementing DEP's own monitors in Freemansburg and East Allentown. Canairy reads that same kind of PurpleAir data continuously, so a spike near a distribution corridor shows up before it becomes a citywide problem.
A river valley that's carried heavy industry for over a century
Allentown sits on the Lehigh River between Blue Mountain to the north and South Mountain to the south, a corridor that has drawn heavy industry since the 1800s: iron and steel works, silk mills, and the cement plant a few miles north in Whitehall, which turned 125 years old in 2024 and still runs today under Holcim/Heidelberg Materials ownership.
Mack Trucks was headquartered in Allentown from 1905 to 2008, and Western Electric's Allentown plant helped mass-produce some of the country's earliest transistors. That legacy of heavy manufacturing sitting close to residential neighborhoods is part of why the valley's air gets watched closely today — and it's largely the same rail and highway corridors that once served steel mills that now carry the warehouse trucks the Lehigh Valley Breathes project is tracking.
Allentown air quality FAQ
What is the air quality in Allentown right now?
As of September 14, 2026 at 8:09 AM EDT, the air quality in Allentown, Pennsylvania is AQI 17 — Good — with PM2.5 at 3.2 µg/m³, the median of 2 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Allentown get Code Orange ozone alerts in summer?
Ground-level ozone forms when heat and sunlight react with vehicle and industrial emissions, and the Lehigh Valley sees Code Orange air quality alerts most summers during heat waves — the Pennsylvania DEP called one on June 3, 2025 and another on May 18, 2026. On those days, anyone with asthma, heart conditions, or breathing trouble is advised to cut back on strenuous outdoor activity.
Does warehouse truck traffic affect Allentown's air quality?
It's enough of a concern that Lehigh and Northampton counties funded their own monitoring project, Lehigh Valley Breathes, which deployed 40 PurpleAir sensors across the region in 2023 specifically to track fine-particle pollution from warehouse-related freight traffic along I-78 and Route 22. Canairy reads that same class of sensor data continuously.
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 2 curated PurpleAir sensors Canairy tracks in and around Allentown, 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 Allentown
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