Flint Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Flint (Flint, MI area) was June 27, 2023, when the daily AQI reached 178 (Unhealthy), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,449 monitored days in 2019–2025, 3 of the 10 worst days were Unhealthy (AQI 151+) or worse; 5 of the 10 were driven by ground-level ozone and 5 by fine particulate matter (PM2.5), and 6 of them fell in 2023. The cleanest day was December 10, 2023 at AQI 7 (Good); the 10 best days span 5 different years.
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When were Flint's worst and best air quality days?
Worst: June 27, 2023, AQI 178 (Unhealthy, PM2.5). Best: December 10, 2023, AQI 7 (Good). Based on 2,449 EPA-monitored days in the Flint, MI area, 2019–2025.
- ✓3 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 112 (Unhealthy for Sensitive Groups).
- ✓Ground-level ozone drove 5 of the 10 worst days.
- ✓2023 accounts for 6 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Flint?▾
June 27, 2023: the Flint, MI area's daily AQI hit 178 (Unhealthy), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,449 monitored days in 2019–2025.
What was the best air quality day in Flint?▾
December 10, 2023, with a daily AQI of 7 (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 Flint's worst air quality day in 2025?▾
June 11, 2025, AQI 126 (Unhealthy for Sensitive Groups), set by ground-level ozone, in peak ozone season.
Which pollutant causes Flint's worst air days?▾
Ground-level ozone set the AQI on 5 of the 10 worst days; fine particulate matter (PM2.5) on 5. The tables above list the defining pollutant for every day.
Flint's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Flint, MI 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) | 178 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2023 page) | 175 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2023 page) | 165 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 4 | (2023 page) | 129 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 5 | (2025 page) | 126 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 6 | (2020 page) | 126 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 7 | (2024 page) | 119 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 8 | (2021 page) | 119 | Unhealthy for Sensitive Groups | O3 — ground-level ozone |
| 9 | (2023 page) | 117 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 10 | (2023 page) | 112 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
Worst day of each year in Flint
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 | 75 | Moderate | PM2.5 — fine particulate matter (PM2.5) | |
| 2020 | 126 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2021 | 119 | Unhealthy for Sensitive Groups | O3 — ground-level ozone | |
| 2022 | 112 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2023 | 178 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 119 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2025 | 126 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
Flint's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Flint, MI area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2023 page) | 7 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 2 | (2021 page) | 8 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 3 | (2024 page) | 10 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 4 | (2023 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2023 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 6 | (2023 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 7 | (2020 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 8 | (2020 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 9 | (2019 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 10 | (2019 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
Right now in Flint
The latest EPA AirNow observation puts Flint's AQI at 20 (PM2.5). The days above are historical records, not today's reading.
View current Flint air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Flint, MI), 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.