Springfield, IL Air Quality in Fall
Across 2019–2025, Springfield's fall (September–November) air quality had a median AQI of 41 (Good) over 634 monitored days in the Springfield, IL area. 0.0% of fall days (0 of 634) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 72.6% of days. The cleanest fall on record here was 2019 (median AQI 37, 0 days above 100) and the worst was 2022 (median 48, 0 days above 100, peak AQI 70).
- Good: 68.3%
- Moderate: 31.7%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Springfield
Today's main pollutant in Springfield is ground-level ozone (AQI 32). 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 Springfield in fall?
Good on a typical day: median AQI 41 across 2019–2025, with 0.0% of fall days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓68.3% of fall days were Good (AQI 0–50), 31.7% Moderate (51–100).
- ✓0 days of 634 reached AQI 101+; the fall peak was 97.
- ✓Cleanest month: October; worst month: September.
Frequently asked questions
What is the air quality like in Springfield in fall?▾
Across 2019–2025, the median daily AQI in Springfield in fall was 41 (Good). 68.3% of days were Good, 31.7% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 634 monitored days in EPA's Air Quality System.
Is fall a good time for outdoor exercise in Springfield?▾
A typical fall day in Springfield sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Which pollutant causes Springfield's fall air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 72.6% of fall days in Springfield. The highest fall AQI recorded in 2019–2025 was 97 (Moderate), in 2022.
Springfield fall air quality, year by year
Springfield fall air quality by year (Springfield, IL, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 90 | 37 | 0 | 75 | PM2.5 |
| 2020 | 91 | 39 | 0 | 80 | PM2.5 |
| 2021 | 89 | 40 | 0 | 78 | PM2.5 |
| 2022worst | 91 | 48 | 0 | 70 | PM2.5 |
| 2023 | 91 | 46 | 0 | 78 | PM2.5 |
| 2024 | 91 | 38 | 0 | 77 | PM2.5 |
| 2025 | 91 | 41 | 0 | 97 | PM2.5 |
What fall air means in Springfield
A typical fall day in Springfield sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Fall's median AQI of 41 is in line with Springfield's whole-year median of 44, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Fall AQI across every EPA metro area (296,275 metro-days, 2019–2025) is 40, so Springfield runs in line with the national Fall norm; 0.0% of its Fall days topped AQI 100 versus 1.5% nationally (below average).
Within the season, October is the cleanest month (median AQI 38, 0.0% of days above 100) and September the worst (median 46, 0.0% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Springfield
The latest EPA AirNow observation puts Springfield's AQI at 32 (O3). The figures above are multi-year season statistics, not today's reading.
View current Springfield air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Springfield, IL), 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.