Pittsburgh Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Pittsburgh (Pittsburgh, PA area) was June 29, 2023, when the daily AQI reached 237 (Very Unhealthy), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,557 monitored days in 2019–2025, 10 of the 10 worst days were Unhealthy (AQI 151+) or worse; 10 of the 10 were driven by fine particulate matter (PM2.5), and 4 of them fell in 2019. The cleanest day was September 30, 2024 at AQI 19 (Good); the 10 best days span 4 different years.
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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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When were Pittsburgh's worst and best air quality days?
Worst: June 29, 2023, AQI 237 (Very Unhealthy, PM2.5). Best: September 30, 2024, AQI 19 (Good). Based on 2,557 EPA-monitored days in the Pittsburgh, PA area, 2019–2025.
- ✓10 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 151 (Unhealthy).
- ✓Fine particulate matter (PM2.5) drove 10 of the 10 worst days.
- ✓2019 accounts for 4 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Pittsburgh?▾
June 29, 2023: the Pittsburgh, PA area's daily AQI hit 237 (Very Unhealthy), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Pittsburgh?▾
September 30, 2024, with a daily AQI of 19 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Pittsburgh's worst air quality day in 2025?▾
June 7, 2025, AQI 131 (Unhealthy for Sensitive Groups), set by fine particulate matter (PM2.5), in wildfire smoke season.
Which pollutant causes Pittsburgh's worst air days?▾
Fine particulate matter (PM2.5) set the AQI on 10 of the 10 worst days. The tables above list the defining pollutant for every day.
Pittsburgh's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Pittsburgh, PA area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2023 page) | 237 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2023 page) | 235 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2023 page) | 175 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 4 | (2019 page) | 165 | Unhealthy | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2019 page) | 164 | Unhealthy | PM2.5 — fine particulate matter (PM2.5) |
| 6 | (2019 page) | 161 | Unhealthy | PM2.5 — fine particulate matter (PM2.5) |
| 7 | (2021 page) | 154 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 8 | (2023 page) | 152 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 9 | (2019 page) | 152 | Unhealthy | PM2.5 — fine particulate matter (PM2.5) |
| 10 | (2022 page) | 151 | Unhealthy | PM2.5 — fine particulate matter (PM2.5) |
Worst day of each year in Pittsburgh
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 165 | Unhealthy | PM2.5 — fine particulate matter (PM2.5) | |
| 2020 | 142 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) | |
| 2021 | 154 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2022 | 151 | Unhealthy | PM2.5 — fine particulate matter (PM2.5) | |
| 2023 | 237 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 129 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2025 | 131 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Pittsburgh's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Pittsburgh, PA area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2024 page) | 19 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 2 | (2023 page) | 20 | Good | O3 — ground-level ozone |
| 3 | (2025 page) | 21 | Good | O3 — ground-level ozone |
| 4 | (2023 page) | 22 | Good | O3 — ground-level ozone |
| 5 | (2021 page) | 22 | Good | O3 — ground-level ozone |
| 6 | (2023 page) | 23 | Good | O3 — ground-level ozone |
| 7 | (2021 page) | 23 | Good | O3 — ground-level ozone |
| 8 | (2024 page) | 24 | Good | O3 — ground-level ozone |
| 9 | (2023 page) | 24 | Good | O3 — ground-level ozone |
| 10 | (2023 page) | 24 | Good | PM2.5 — fine particulate matter (PM2.5) |
Right now in Pittsburgh
The latest EPA AirNow observation puts Pittsburgh's AQI at 56 (PM2.5). The days above are historical records, 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.