Median AQI
45
Good
Illinois · County air quality · 2025
Kane County, Illinois
Median AQI 45 (Good). 61.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 45
- Median AQI
- 61.9%
- Good-air days
- 1
- Unhealthy days
- 17%
- Cleaner than US counties
Kane County's 2025 annual median AQI is 45 (Good), with 61.9% Good days
According to the U.S. EPA Air Quality System, Kane County, Illinois posted a 2025 median AQI of 45 (Good) across 365 monitored days, with 61.9% rated Good and 1 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Kane County's 61.9% Good-day share places it cleaner than 17% of US counties in 2025.
- Closest median-AQI peer
- Baltimore County (64.7% Good, median AQI 45) is the closest nationwide median-AQI peer to Kane County.
- 2020–2025 trend
- Kane County's floor-qualifying Good-day share is worsening from 2020 to 2025 (73.1% → 61.9%).
- Median AQI
- Median AQI: 45
The verdict
According to EPA Air Quality System monitoring data, Kane County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 45 with 61.9% of 365 monitored days in the Good band, driven mainly by PM2.5.
- 45
- median AQI · Good
- 61.9%
- days rated Good
- PM2.5
- main pollutant
- 17%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 165.
Annual release change
What changed in the 2025 EPA annual release
- Kane County's Good-day share fell from 72.3% to 61.9% between the 2024 and 2025 EPA annual releases, a change of -10.3 percentage points.
- Kane County's peak single-day AQI rose from 105 to 165 between the 2024 and 2025 EPA annual releases, a change of +60 points.
- Kane County's median AQI rose from 42 to 45 between the 2024 and 2025 EPA annual releases, a change of +3 points.
- Kane County's Unhealthy-category days rose from 0 to 1 between the 2024 and 2025 EPA annual releases, a change of +1 days.
Data updated August 2026
- Good · 226 d · 61.9%
- Moderate · 130 d · 35.6%
- USG · 8 d · 2.2%
- Unhealthy · 1 d · 0.3%
How did Kane County's air break down in 2025?
Across 365 monitored days, 226 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 165 (Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 365 days monitored. Median AQI: 45 (Good).
Insights: Kane County, Illinois. EPA monitors recorded a median Air Quality Index of 45 across 365 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 226 (62%) fell in the Good band (AQI 0–50), 130 (36%) registered Moderate readings, and 8 (2%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 73, while the worst single-day peak hit 165 (Unhealthy). Residents averaged about 18.6 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (220 days), Ozone (145 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -11.2 points (measured against 279 monitored days in 2020 and 365 in 2025, so raw day counts are not comparable) and the median AQI moved +3 points, placing the multi-year trajectory at worsening. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Adams (94.7% good, AQI 38); Champaign (65.8% good, AQI 43); Clark (93.8% good, AQI 33); Cook (40.8% good, AQI 53); DuPage (63.8% good, AQI 42); Effingham (95.5% good, AQI 35).
Air Quality Summary
Good Days
61.9%
226 of 365 monitored days
-13.1pp vs 75% target
Max AQI Recorded
165
Unhealthy
Health Grade
Moderate
90th-pct AQI 73
Kane County, Good days share 61.9%
National avg
Share of monitored days at AQI 0-50 (Good band).
Kane County, Unhealthy-or-worse share 2.7%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
226
62%
Moderate
130
36%
USG
8
2%
Unhealthy
1
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Kane County.
- PM2.5 · 220 days · 60.3%
- Ozone · 145 days · 39.7%
Health Impact Assessment
Moderate
Kane County's air quality is rated Moderate based on 61.9% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 8 days reached "Unhealthy for Sensitive Groups" (AQI 101-150) and peak AQI reached 165. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 220 of 365 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Kane County. Highest Good-day share: 2020 (73.1%, 204 of 279 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 204 | 68 | 6 | 1 | 42 | 161 |
| 2021 | 188 | 96 | 1 | 0 | 44 | 112 |
| 2022 | 189 | 93 | 3 | 0 | 42 | 129 |
| 2023 | 178 | 89 | 16 | 5 | 46 | 174 |
| 2024 | 237 | 90 | 1 | 0 | 42 | 105 |
| 2025 | 226 | 130 | 8 | 1 | 45 | 165 |
How does Kane County compare?
How Kane County compares
Good-day share worse than typical
Kane County 61.9%
Baltimore County, Maryland 64.7%
Typical US county 76.0%
Median AQI worse than typical
Kane County 45
Baltimore County, Maryland 45
Typical US county 39
Unhealthy days / yr about typical
Kane County 1
Baltimore County, Maryland 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Kane County (45), not geographic neighbors.
Baltimore County, Maryland
Median AQI 45 · 64.7% Good-day share
Bell County, Texas
Median AQI 45 · 66.0% Good-day share
Box Elder County, Utah
Median AQI 45 · 64.7% Good-day share
Bronx County, New York
Median AQI 45 · 59.2% Good-day share
Catano County, Puerto Rico
Median AQI 45 · 60.6% Good-day share
Catron County, New Mexico
Median AQI 45 · 71.7% Good-day share
Same primary pollutant: PM2.5
PM2.5 led the AQI on the most monitored days here. These peers share that driver and the closest Good-day share (a second relationship type beyond median-AQI neighbors).
Daviess County, Kentucky
61.9% Good-day share · median AQI 43
Yakima County, Washington
61.9% Good-day share · median AQI 41
Wyandotte County, Kansas
61.9% Good-day share · median AQI 45
Asotin County, Washington
61.9% Good-day share · median AQI 42
Livingston County, Louisiana
62.0% Good-day share · median AQI 45
Calcasieu County, Louisiana
62.2% Good-day share · median AQI 47
Illinois counties on the map
Geographic containment only, other monitored counties in Illinois, independent of AQI or pollutant match.
What Kane County's air means for you
On most days the air here is fine, but PM2.5 drives 1 unhealthy-or-worse day a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 45 means for exposure. Health guidance
- See how Kane County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Kane County with its Illinois neighbours before drawing a conclusion about the region. All of Illinois
Based on 365 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
Keep exploring the annual AQI record
Air-quality reading list
Frequently Asked Questions
What is the air quality in Kane County, Illinois? ▼
Kane County has a median Air Quality Index (AQI) of 45, rated "Good." 61.9% of monitored days (226 out of 365) had good air quality in 2025.
What is the main pollutant in Kane County? ▼
The primary pollutant in Kane County is Fine Particles (PM2.5), which was the main AQI driver on 220 days (60% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Kane County have? ▼
In 2025, Kane County recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 165.
Is the air quality in Kane County getting better or worse? ▼
Air quality in Kane County is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 73.1% (204 of 279 days). Lowest qualifying Good-day share: 2023 at 61.8% (178 of 288 days).
What does AQI 45 mean for health? ▼
Kane County's median AQI of 45 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Kane County compare to other counties in Illinois? ▼
Kane County has 61.9% good air days. Nearby counties in Illinois: Adams (94.7% good), Champaign (65.8% good), Clark (93.8% good), Cook (40.8% good), DuPage (63.8% good), Effingham (95.5% good).
What is the 90th percentile AQI in Kane County? ▼
The 90th percentile AQI for Kane County is 73, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 165 (Unhealthy).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Kane County, Illinois · 2020–2025
Share this annual record
Send the source-year summary or download its ready-to-use data card.
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.