Harrisburg Air Quality in 2021
In 2021, Harrisburg's air quality (Harrisburg-Carlisle, PA area) had a median daily AQI of 52 (Moderate) across 365 monitored days. 2 days (0.5%) reached Unhealthy for Sensitive Groups or worse, 157 were Good, and the year's peak AQI was 127 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 290 of those days. The cleanest month of 2021 was May (median AQI 41, 0 days above 100) and the worst was July (median 57, 2 days above 100, peak 127).
- Good: 43.0%
- Moderate: 56.4%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
Extra Protection for Harrisburg Homes
Air quality in Harrisburg is moderate (AQI 52), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How was Harrisburg's air quality in 2021?
Moderate on a typical day: median AQI 52, with 2 days above AQI 100 out of 365 monitored — the 3rd cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 127 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 290 days.
- ✓Cleanest month: May; worst: July.
Frequently asked questions
What was the average AQI in Harrisburg in 2021?▾
EPA's Air Quality System puts Harrisburg's (Harrisburg-Carlisle, PA) median daily AQI for 2021 at 52, which is Moderate. 2 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 127.
Which month had the worst air quality in Harrisburg in 2021?▾
The cleanest month of 2021 was May (median AQI 41, 0 days above 100) and the worst was July (median 57, 2 days above 100, peak 127).
Was 2021 a good or bad year for Harrisburg's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 3rd cleanest by days above AQI 100. 2021's median of 52 is in line with the area's typical annual median of 50.
Harrisburg month by month in 2021
Harrisburg air quality month by month, 2021 (Harrisburg-Carlisle, PA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 46 | 0 | 94 | PM2.5 |
| February | 28 | 54 | 0 | 83 | PM2.5 |
| March | 31 | 42 | 0 | 87 | PM2.5 |
| April | 30 | 53 | 0 | 73 | PM2.5 |
| Maycleanest | 31 | 41 | 0 | 100 | O3 |
| June | 30 | 51 | 0 | 80 | PM2.5 |
| Julyworst | 31 | 57 | 2 | 127 | PM2.5 |
| August | 31 | 55 | 0 | 80 | PM2.5 |
| September | 30 | 43 | 0 | 76 | PM2.5 |
| October | 31 | 52 | 0 | 62 | PM2.5 |
| November | 30 | 52 | 0 | 83 | PM2.5 |
| December | 31 | 60 | 0 | 85 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 3rd cleanest by days above AQI 100.
2021's median of 52 is in line with the area's typical annual median of 50.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Harrisburg
The latest EPA AirNow observation puts Harrisburg's AQI at 52 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Harrisburg air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Harrisburg-Carlisle, PA), 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.