Peoria Air Quality in 2021
In 2021, Peoria's air quality (Peoria, IL area) had a median daily AQI of 50 (Good) across 361 monitored days. 1 day (0.3%) reached Unhealthy for Sensitive Groups or worse, 181 were Good, and the year's peak AQI was 101 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 269 of those days. The cleanest month of 2021 was October (median AQI 35, 0 days above 100) and the worst was June (median 54, 1 day above 100, peak 101).
- Good: 50.1%
- Moderate: 49.6%
- Unhealthy for Sensitive Groups: 0.3%
- Unhealthy or worse: 0.0%
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How was Peoria's air quality in 2021?
Good on a typical day: median AQI 50, with 1 day above AQI 100 out of 361 monitored — the 4th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 101 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 269 days.
- ✓Cleanest month: October; worst: June.
Frequently asked questions
What was the average AQI in Peoria in 2021?▾
EPA's Air Quality System puts Peoria's (Peoria, IL) median daily AQI for 2021 at 50, which is Good. 1 day were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 101.
Which month had the worst air quality in Peoria in 2021?▾
The cleanest month of 2021 was October (median AQI 35, 0 days above 100) and the worst was June (median 54, 1 day above 100, peak 101).
Was 2021 a good or bad year for Peoria's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 4th cleanest by days above AQI 100. 2021's median of 50 is above the area's typical annual median of 45.
Peoria month by month in 2021
Peoria air quality month by month, 2021 (Peoria, IL, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 27 | 49 | 0 | 67 | PM2.5 |
| February | 28 | 51 | 0 | 75 | PM2.5 |
| March | 31 | 51 | 0 | 70 | PM2.5 |
| April | 30 | 49 | 0 | 87 | PM2.5 |
| May | 31 | 47 | 0 | 61 | PM2.5 |
| Juneworst | 30 | 54 | 1 | 101 | O3 |
| July | 31 | 55 | 0 | 97 | PM2.5 |
| August | 31 | 53 | 0 | 86 | PM2.5 |
| September | 30 | 48 | 0 | 74 | O3 |
| Octobercleanest | 31 | 35 | 0 | 65 | PM2.5 |
| November | 30 | 52 | 0 | 89 | PM2.5 |
| December | 31 | 57 | 0 | 71 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 4th cleanest by days above AQI 100.
2021's median of 50 is above the area's typical annual median of 45.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Peoria
The latest EPA AirNow observation puts Peoria's AQI at 40 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Peoria air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Peoria, 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.