Air Quality in Allentown, Pennsylvania — Live

Live readings from PurpleAir sensors across Allentown — with free alerts when summer ozone or warehouse-corridor pollution builds.

Live Allentown AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Allentown and Bethlehem, Easton, Emmaus, Whitehall.

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.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

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?

This page shows the current AQI for Allentown, calculated from PurpleAir sensors across the city and updated continuously. The map below shows every live sensor, so you can check the reading closest to your own neighborhood.

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 AQI level is unhealthy?

Under the US EPA scale, AQI 0-50 is Good and 51-100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups - kids, older adults, and people with asthma or heart conditions - and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Where does Canairy's Allentown data come from?

Readings come from PurpleAir's network of laser particle sensors across Allentown and surrounding towns, cross-referenced with government monitors and the Google Air Quality API. You can see every sensor behind your numbers on the live map - there's no black box.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Get Canairy free on Google Play.