Pittsburgh Air Quality in Winter
Across 2019–2025, Pittsburgh's winter (December–February) air quality had a median AQI of 56 (Moderate) over 632 monitored days in the Pittsburgh, PA area. 2.8% of winter days (18 of 632) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 91.9% of days. The cleanest winter on record here was 2025 (median AQI 51, 0 days above 100) and the worst was 2019 (median 60, 10 days above 100, peak AQI 165).
- Good: 28.0%
- Moderate: 69.1%
- Unhealthy for Sensitive Groups: 2.2%
- Unhealthy or worse: 0.6%
Extra Protection for Pittsburgh Homes
Air quality in Pittsburgh is moderate (AQI 56), 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.
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How is the air in Pittsburgh in winter?
Moderate on a typical day: median AQI 56 across 2019–2025, with 2.8% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓28.0% of winter days were Good (AQI 0–50), 69.1% Moderate (51–100).
- ✓18 days of 632 reached AQI 101+; the winter peak was 165.
- ✓Cleanest month: January; worst month: December.
Frequently asked questions
What is the air quality like in Pittsburgh in winter?▾
Across 2019–2025, the median daily AQI in Pittsburgh in winter was 56 (Moderate). 28.0% of days were Good, 69.1% Moderate, and 2.8% reached Unhealthy for Sensitive Groups or worse, based on 632 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Pittsburgh?▾
A typical winter day in Pittsburgh is Moderate (median AQI 56): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 36 of winter days (2.8%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Pittsburgh's winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 91.9% of winter days in Pittsburgh. The highest winter AQI recorded in 2019–2025 was 165 (Unhealthy), in 2019.
Pittsburgh winter air quality, year by year
Pittsburgh winter air quality by year (Pittsburgh, PA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 90 | 60 | 10 | 165 | PM2.5 |
| 2020 | 91 | 56 | 3 | 142 | PM2.5 |
| 2021 | 90 | 57 | 1 | 107 | PM2.5 |
| 2022 | 90 | 60 | 1 | 145 | PM2.5 |
| 2023 | 90 | 57 | 2 | 108 | PM2.5 |
| 2024 | 91 | 53 | 1 | 103 | PM2.5 |
| 2025cleanest | 90 | 51 | 0 | 94 | PM2.5 |
What winter air means in Pittsburgh
A typical winter day in Pittsburgh is Moderate (median AQI 56): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 36 of winter days (2.8%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Winter's median AQI of 56 is in line with Pittsburgh's whole-year median of 58, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Pittsburgh runs above the national Winter norm; 2.8% of its Winter days topped AQI 100 versus 0.6% nationally (above average).
Within the season, January is the cleanest month (median AQI 56, 0.5% of days above 100) and December the worst (median 56, 4.6% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Pittsburgh
The latest EPA AirNow observation puts Pittsburgh's AQI at 56 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Pittsburgh air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Pittsburgh, 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.