Harrisburg Air Quality in March
Across 2019–2025, Harrisburg's March air quality had a median AQI of 46 (Good) over 217 monitored days in the Harrisburg-Carlisle, PA area. 0.5% of March days (1 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 61.3% of days. The cleanest March on record here was 2024 (median AQI 40, 0 days above 100) and the worst was 2019 (median 55, 1 day above 100, peak AQI 111).
- Good: 59.4%
- Moderate: 40.1%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
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 March?
Good on a typical day: median AQI 46 across 2019–2025, with 0.5% of March days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓59.4% of March days were Good (AQI 0–50), 40.1% Moderate (51–100).
- ✓1 day of 217 reached AQI 101+; the March peak was 111.
- ✓Best March: 2024; worst March: 2019.
Frequently asked questions
What is the air quality like in Harrisburg in March?▾
Across 2019–2025, the median daily AQI in Harrisburg in March was 46 (Good). 59.4% of days were Good, 40.1% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is March a good time for outdoor exercise in Harrisburg?▾
A typical March day in Harrisburg sits in the Good range (median AQI 46), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.
Which pollutant causes Harrisburg's March air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 61.3% of March days in Harrisburg. The highest March AQI recorded in 2019–2025 was 111 (Unhealthy for Sensitive Groups), in 2019.
Harrisburg March air quality, year by year
Harrisburg March air quality by year (Harrisburg-Carlisle, PA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 31 | 55 | 1 | 111 | PM2.5 |
| 2020 | 31 | 48 | 0 | 67 | PM2.5 |
| 2021 | 31 | 42 | 0 | 87 | PM2.5 |
| 2022 | 31 | 49 | 0 | 70 | PM2.5 |
| 2023 | 31 | 46 | 0 | 72 | PM2.5 |
| 2024cleanest | 31 | 40 | 0 | 67 | O3 |
| 2025 | 31 | 43 | 0 | 70 | O3 |
What March air means in Harrisburg
A typical March day in Harrisburg sits in the Good range (median AQI 46), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.
March's median AQI of 46 is below Harrisburg's whole-year median of 50, making it one of the area's cleaner periods. Nationally, the median March AQI across every EPA metro area (102,455 metro-days, 2019–2025) is 42, so Harrisburg runs above the national March norm; 0.5% of its March days topped AQI 100 versus 0.4% nationally (about the same).
March is part of Harrisburg's spring season (March, April, May); the spring page pools all three months.
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 month 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.