Allentown, Pennsylvania Air Quality
Allentown has a median AQI of 42, earning an air quality grade of A- — excellent air quality that ranks better than 44% of US cities. Air quality has been improving steadily over the past decade, a positive sign for residents. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Allentown recorded 146 good air quality days (70% of monitored days) and 1 unhealthy days.
Population: 644,758 • County: Lehigh
Current AQI
Quick Facts
| Current AQI | 14 — Good |
| Air Quality Grade | A- |
| Median AQI (2025) | 42 |
| vs. U.S. Cities | Better than 44% |
| Primary Pollutant | Ozone |
| Unhealthy Days/Year | 1 |
| 10-Year Trend | ↑ Improving |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Allentown is sourced from the Allentown monitoring area, located approximately 3 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Major roadways in the area include I-78, US-22, and PA-309. Heavy vehicle traffic on these corridors is a primary source of nitrogen dioxide, carbon monoxide, and fine particulate matter (PM2.5).
Key local pollution sources include vehicle traffic, upwind NJ and NY emissions, manufacturing corridor, and freight.
AQI Trend (10 Years)
Air Quality Days by Year
Allentown Median AQI by Year
Annual EPA air quality data for Allentown — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 42 | 146 | 1 | 115 | Ozone |
| 2024 | 39 | 267 | 2 | 119 | Ozone |
| 2023 | 43 | 230 | 7 | 337 | PM2.5 |
| 2022 | 42 | 246 | — | 99 | PM2.5 |
| 2021 | 47 | 198 | 1 | 154 | PM2.5 |
| 2020 | 41 | 262 | — | 93 | PM2.5 |
| 2019 | 43 | 254 | 3 | 119 | PM2.5 |
| 2018 | 43 | 221 | 2 | 126 | PM2.5 |
| 2017 | 44 | 241 | 1 | 115 | Ozone |
| 2016 | 52 | 156 | 6 | 129 | PM2.5 |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About Allentown Air Quality
What is the air quality in Allentown today?
The current AQI in Allentown is 14, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Allentown getting better or worse?
Air quality in Allentown has been improving. The median AQI has dropped 10 points (from 52 in 2016 to 42 in 2025), a positive trend for residents.
What is the most common air pollutant in Allentown?
Ozone is the primary air pollutant in Allentown, responsible for 114 days (55% of monitored days) in 2025. Ground-level ozone forms when sunlight reacts with emissions from vehicles and industry, typically peaking on hot summer afternoons.
How many unhealthy air days does Allentown have per year?
In 2025, Allentown recorded 70% good air quality days (146 days) out of 208 monitored days. There were 1 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 115.
What air quality grade does Allentown receive?
Allentown receives an air quality grade of A-, placing it better than 44% of US cities. This is based on a median AQI of 42 in 2025, with 146 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 44% of US cities
Nearby Cities
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National Rankings
See how Allentown compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Allentown
Ozone is Allentown's primary pollutant. Standard HEPA filters don't capture ozone molecules — you need activated carbon or PECO technology to chemically break them down. We highlight those units here.
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