Springfield, IL Air Quality in 2023

In 2023, Springfield's air quality (Springfield, IL area) had a median daily AQI of 51 (Moderate) across 365 monitored days. 20 days (5.5%) reached Unhealthy for Sensitive Groups or worse, 182 were Good, and the year's peak AQI was 247 (Very Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 253 of those days. The cleanest month of 2023 was October (median AQI 37, 0 days above 100) and the worst was June (median 82, 13 days above 100, peak 247).

51
Median AQI
Moderate
20
Days above AQI 100
5.5% of 365 days
74
90th percentile AQI
worst 1 day in 10
247
Peak AQI
Very Unhealthy
PM2.5
Main pollutant
253 of 365 days
182
Good days
49.9% of days
  • Good: 49.9%
  • Moderate: 44.7%
  • Unhealthy for Sensitive Groups: 4.7%
  • Unhealthy or worse: 0.8%

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QUICK ANSWER

How was Springfield's air quality in 2023?

Moderate on a typical day: median AQI 51, with 20 days above AQI 100 out of 365 monitored — the 7th cleanest of 7 years on record for the area.

  • Peak AQI in 2023: 247 (Very Unhealthy).
  • Fine particulate matter (PM2.5) was the main pollutant on 253 days.
  • Cleanest month: October; worst: June.

Frequently asked questions

What was the average AQI in Springfield in 2023?

EPA's Air Quality System puts Springfield's (Springfield, IL) median daily AQI for 2023 at 51, which is Moderate. 20 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 247.

Which month had the worst air quality in Springfield in 2023?

The cleanest month of 2023 was October (median AQI 37, 0 days above 100) and the worst was June (median 82, 13 days above 100, peak 247).

Was 2023 a good or bad year for Springfield's air?

Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 7th cleanest by days above AQI 100 — the worst year on record here. 2023's median of 51 is above the area's typical annual median of 44.

Springfield month by month in 2023

Springfield air quality month by month, 2023 (Springfield, IL, EPA AQS daily AQI)

MonthDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
January3146068PM2.5
February2838064PM2.5
March3147069PM2.5
April3047071O3
May31636133O3
Juneworst308213247O3
July31541133PM2.5
August3155077PM2.5
September3054078PM2.5
Octobercleanest3137075PM2.5
November3042060PM2.5
December3138063PM2.5

How 2023 compares

Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 7th cleanest by days above AQI 100 — the worst year on record here.

2023's median of 51 is above the area's typical annual median of 44.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Springfield

The latest EPA AirNow observation puts Springfield's AQI at 25 (PM2.5). The figures above are multi-year annual 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.