Allentown Air Quality in 2021
In 2021, Allentown's air quality (Allentown-Bethlehem-Easton, PA-NJ area) had a median daily AQI of 51 (Moderate) across 365 monitored days. 4 days (1.1%) reached Unhealthy for Sensitive Groups or worse, 182 were Good, and the year's peak AQI was 154 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 247 of those days. The cleanest month of 2021 was September (median AQI 43, 0 days above 100) and the worst was May (median 49, 2 days above 100, peak 105).
- Good: 49.9%
- Moderate: 49.0%
- Unhealthy for Sensitive Groups: 0.8%
- Unhealthy or worse: 0.3%
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How was Allentown's air quality in 2021?
Moderate on a typical day: median AQI 51, with 4 days above AQI 100 out of 365 monitored — the 6th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 154 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 247 days.
- ✓Cleanest month: September; worst: May.
Frequently asked questions
What was the average AQI in Allentown in 2021?▾
EPA's Air Quality System puts Allentown's (Allentown-Bethlehem-Easton, PA-NJ) median daily AQI for 2021 at 51, which is Moderate. 4 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 154.
Which month had the worst air quality in Allentown in 2021?▾
The cleanest month of 2021 was September (median AQI 43, 0 days above 100) and the worst was May (median 49, 2 days above 100, peak 105).
Was 2021 a good or bad year for Allentown's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 6th cleanest by days above AQI 100. 2021's median of 51 is above the area's typical annual median of 46.
Allentown month by month in 2021
Allentown air quality month by month, 2021 (Allentown-Bethlehem-Easton, PA-NJ, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 46 | 0 | 91 | PM2.5 |
| February | 28 | 52 | 0 | 75 | PM2.5 |
| March | 31 | 44 | 0 | 82 | PM2.5 |
| April | 30 | 48 | 0 | 71 | O3 |
| Mayworst | 31 | 49 | 2 | 105 | O3 |
| June | 30 | 53 | 1 | 108 | PM2.5 |
| July | 31 | 62 | 1 | 154 | PM2.5 |
| August | 31 | 55 | 0 | 97 | PM2.5 |
| Septembercleanest | 30 | 43 | 0 | 68 | PM2.5 |
| October | 31 | 47 | 0 | 66 | PM2.5 |
| November | 30 | 53 | 0 | 72 | PM2.5 |
| December | 31 | 55 | 0 | 82 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 6th cleanest by days above AQI 100.
2021's median of 51 is above the area's typical annual median of 46.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Allentown
The latest EPA AirNow observation puts Allentown's AQI at 33 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Allentown air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Allentown-Bethlehem-Easton, PA-NJ), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.