Indianapolis Air Quality in January
Across 2019–2025, Indianapolis's January air quality had a median AQI of 57 (Moderate) over 217 monitored days in the Indianapolis-Carmel-Anderson, IN area. 0.9% of January days (2 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 96.3% of days. The cleanest January on record here was 2025 (median AQI 47, 0 days above 100) and the worst was 2022 (median 59, 2 days above 100, peak AQI 107).
- Good: 26.3%
- Moderate: 72.8%
- Unhealthy for Sensitive Groups: 0.9%
- Unhealthy or worse: 0.0%
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How is the air in Indianapolis in January?
Moderate on a typical day: median AQI 57 across 2019–2025, with 0.9% of January days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓26.3% of January days were Good (AQI 0–50), 72.8% Moderate (51–100).
- ✓2 days of 217 reached AQI 101+; the January peak was 107.
- ✓Best January: 2025; worst January: 2022.
Frequently asked questions
What is the air quality like in Indianapolis in January?▾
Across 2019–2025, the median daily AQI in Indianapolis in January was 57 (Moderate). 26.3% of days were Good, 72.8% Moderate, and 0.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is January a good time for outdoor exercise in Indianapolis?▾
A typical January day in Indianapolis is Moderate (median AQI 57): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of January days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Indianapolis's January air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 96.3% of January days in Indianapolis. The highest January AQI recorded in 2019–2025 was 107 (Unhealthy for Sensitive Groups), in 2022.
Indianapolis January air quality, year by year
Indianapolis January air quality by year (Indianapolis-Carmel-Anderson, IN, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 56 | 0 | 77 | PM2.5 |
| 2020 | 31 | 58 | 0 | 74 | PM2.5 |
| 2021 | 31 | 58 | 0 | 81 | PM2.5 |
| 2022worst | 31 | 59 | 2 | 107 | PM2.5 |
| 2023 | 31 | 59 | 0 | 87 | PM2.5 |
| 2024 | 31 | 54 | 0 | 68 | PM2.5 |
| 2025cleanest | 31 | 47 | 0 | 86 | PM2.5 |
What January air means in Indianapolis
A typical January day in Indianapolis is Moderate (median AQI 57): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of January days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
January's median AQI of 57 is in line with Indianapolis's whole-year median of 56, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median January AQI across every EPA metro area (95,602 metro-days, 2019–2025) is 39, so Indianapolis runs above the national January norm; 0.9% of its January days topped AQI 100 versus 0.7% nationally (about the same).
January is part of Indianapolis's winter season (December, January, February); the winter page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Indianapolis
The latest EPA AirNow observation puts Indianapolis's AQI at 55 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Indianapolis air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Indianapolis-Carmel-Anderson, IN), 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.