Percy, Illinois Air Quality
Percy has a median AQI of 44, earning an air quality grade of A- — excellent air quality that ranks better than 31% of US cities. Air quality has remained relatively stable over the past decade. Particulate matter (PM2.5) is the primary concern, often linked to vehicle traffic, industrial activity, and wildfire smoke. In 2025, Percy recorded 182 good air quality days (67% of monitored days) and 1 unhealthy days.
Population: 921 • County: Randolph
Current AQI
Quick Facts
| Current AQI | 24 — Good |
| Air Quality Grade | A- |
| Median AQI (2025) | 44 |
| vs. U.S. Cities | Better than 31% |
| Primary Pollutant | PM2.5 |
| Unhealthy Days/Year | 1 |
| 10-Year Trend | → Stable |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Percy is sourced from the HOUSTON monitoring area, located approximately 14 miles from city center. This EPA-certified station continuously tracks particulate matter (PM2.5), the primary driver of air quality alerts in this area.
Percy tends to see elevated PM2.5 readings during fall and winter months when temperature inversions trap pollutants near the surface. Wood burning, vehicle exhaust, and reduced wind speeds compound the effect. Residents with respiratory conditions should monitor forecasts closely between November and February.
AQI Trend (10 Years)
Air Quality Days by Year
Percy Median AQI by Year
Annual EPA air quality data for Percy — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 44 | 182 | 1 | 161 | PM2.5 |
| 2024 | 40 | 289 | — | 100 | PM2.5 |
| 2023 | 46 | 215 | 13 | 156 | PM2.5 |
| 2022 | 45 | 244 | 2 | 108 | PM2.5 |
| 2021 | 45 | 223 | 1 | 122 | PM2.5 |
| 2020 | 44 | 243 | 2 | 103 | PM2.5 |
| 2019 | 43 | 234 | — | 97 | Ozone |
| 2018 | 46 | 225 | 1 | 129 | PM2.5 |
| 2017 | 52 | 153 | 1 | 115 | PM2.5 |
| 2016 | 42 | 209 | 1 | 119 | Ozone |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About Percy Air Quality
What is the air quality in Percy today?
The current AQI in Percy is 24, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Percy getting better or worse?
Air quality in Percy has been stable. The median AQI has risen 2 points (from 42 in 2016 to 44 in 2025).
What is the most common air pollutant in Percy?
PM2.5 is the primary air pollutant in Percy, responsible for 154 days (57% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does Percy have per year?
In 2025, Percy recorded 67% good air quality days (182 days) out of 272 monitored days. There were 0 Unhealthy for Sensitive Groups days and 1 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 161.
What air quality grade does Percy receive?
Percy receives an air quality grade of A-, placing it better than 31% of US cities. This is based on a median AQI of 44 in 2025, with 182 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 31% of US cities
Nearby Cities
Get AQI Alerts
Receive notifications when air quality changes in Percy
National Rankings
See how Percy compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Percy
Percy sees its worst PM2.5 during winter temperature inversions when particulates get trapped near ground level. A unit with True HEPA and an auto-mode sensor is most effective for responding to these spikes.
Blueair Blue Pure 211+
High performance for large rooms with simple operation.
- ✓Good room size match
- ✓Recommended for your air quality
- ✓High performance
We may earn a commission from purchases
Other Great Options
Molekule Air Pro
Commercial-grade with patented PECO technology for destroying pollutants.
Honeywell HPA300
Powerful workhorse for large rooms. Built to last.
Coway Airmega AP-1512HH
Best overall value for medium rooms. Excellent performance at an affordable price.
Not sure which air purifier is right for you?
Learn more about different types of air purifiers and how to choose the best one for your needs.
Read our complete buying guide →