Harrisburg Air Quality in Summer
Across 2019–2025, Harrisburg's summer (June–August) air quality had a median AQI of 53 (Moderate) over 644 monitored days in the Harrisburg-Carlisle, PA area. 2.7% of summer days (17 of 644) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 63.7% of days. The cleanest summer on record here was 2020 (median AQI 50, 0 days above 100) and the worst was 2023 (median 57, 11 days above 100, peak AQI 255).
- Good: 40.4%
- Moderate: 57.0%
- Unhealthy for Sensitive Groups: 1.9%
- Unhealthy or worse: 0.8%
Reduce Indoor Ozone in Harrisburg
Today's main pollutant in Harrisburg is ground-level ozone (AQI 48). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Harrisburg in summer?
Moderate on a typical day: median AQI 53 across 2019–2025, with 2.7% of summer days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓40.4% of summer days were Good (AQI 0–50), 57.0% Moderate (51–100).
- ✓17 days of 644 reached AQI 101+; the summer peak was 255.
- ✓Cleanest month: August; worst month: June.
Frequently asked questions
What is the air quality like in Harrisburg in summer?▾
Across 2019–2025, the median daily AQI in Harrisburg in summer was 53 (Moderate). 40.4% of days were Good, 57.0% Moderate, and 2.7% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is summer a good time for outdoor exercise in Harrisburg?▾
A typical summer day in Harrisburg is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 37 of summer days (2.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Harrisburg's summer air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 63.7% of summer days in Harrisburg. The highest summer AQI recorded in 2019–2025 was 255 (Very Unhealthy), in 2023.
Harrisburg summer air quality, year by year
Harrisburg summer air quality by year (Harrisburg-Carlisle, PA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 52 | 0 | 100 | PM2.5 |
| 2020cleanest | 92 | 50 | 0 | 87 | PM2.5 |
| 2021 | 92 | 54 | 2 | 127 | PM2.5 |
| 2022 | 92 | 52 | 1 | 112 | PM2.5 |
| 2023worst | 92 | 57 | 11 | 255 | PM2.5 |
| 2024 | 92 | 53 | 2 | 105 | O3 |
| 2025 | 92 | 52 | 1 | 101 | PM2.5 |
What summer air means in Harrisburg
A typical summer day in Harrisburg is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 37 of summer days (2.7%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Summer's median AQI of 53 is in line with Harrisburg's whole-year median of 50, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Summer AQI across every EPA metro area (308,645 metro-days, 2019–2025) is 46, so Harrisburg runs above the national Summer norm; 2.7% of its Summer days topped AQI 100 versus 3.6% nationally (about the same).
Within the season, August is the cleanest month (median AQI 51, 0.5% of days above 100) and June the worst (median 52, 5.3% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Harrisburg
The latest EPA AirNow observation puts Harrisburg's AQI at 48 (O3). The figures above are multi-year season 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.