Median AQI
43
Good
Kansas · County air quality · 2025
Sumner County, Kansas
Median AQI 43 (Good). 67.4% of monitored days rated Good, direct from EPA Air Quality System stations.
- 43
- Median AQI
- 67.4%
- Good-air days
- 1
- Unhealthy days
- 27%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Sumner County's air is good on balance, more polluted than the median US county, a median AQI of 43 with 67.4% of 181 monitored days in the Good band, driven mainly by PM2.5.
- 43
- median AQI · Good
- 67.4%
- days rated Good
- PM2.5
- main pollutant
- 27%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 370.
Data updated July 2026
- Good · 122 d · 67.4%
- Moderate · 56 d · 30.9%
- USG · 2 d · 1.1%
- Hazardous · 1 d · 0.6%
How did Sumner County's air break down in 2025?
Across 181 monitored days, 122 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 370 (Hazardous).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 43 (Good).
Insights: Sumner County, Kansas. EPA monitors recorded a median Air Quality Index of 43 across 181 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 122 (67%) fell in the Good band (AQI 0–50), 56 (31%) registered Moderate readings, and 2 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 63, while the worst single-day peak hit 370 (Hazardous). Residents averaged about 20.2 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (129 days), Ozone (38 days), PM10 (14 days). Across the 2020–2025 trend window, good days shifted by -109 and the median AQI moved -2 points, placing the multi-year trajectory at improving. Residents and visitors experienced 1 unhealthy-or-worse days combined, periods when the EPA recommends sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Chase (88.9% good, AQI 22); Douglas (90.7% good, AQI 41); Ford (89.4% good, AQI 26); Johnson (71.8% good, AQI 43); Leavenworth (93.9% good, AQI 36); Neosho (73.5% good, AQI 43).
Air Quality Summary
Good Days
67.4%
122 of 181 monitored days
-7.6pp vs 75% target
Max AQI Recorded
370
Hazardous
Health Grade
Moderate
90th-pct AQI 63
Sumner County, Good days share 67.4%
National avg
Share of monitored days at AQI 0-50 (Good band).
Sumner County, Unhealthy-or-worse share 0.6%
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 181 monitored days across EPA AQI categories.
Good
122
67%
Moderate
56
31%
USG
2
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
1
1%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Sumner County.
- PM2.5 · 129 days · 71.3%
- Ozone · 38 days · 21.0%
- PM10 · 14 days · 7.7%
Health Impact Assessment
Moderate
Sumner County's air quality is rated Moderate based on 67.4% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality posed significant health risk in 2025. Sensitive groups, including people with asthma, COPD, cardiovascular conditions, children, pregnant women, and adults over 65, should monitor AirNow.gov alerts and limit outdoor activity on Unhealthy (AQI 151+) and Very Unhealthy (201+) days. Peak readings reached AQI 370, well into the Hazardous range.
Sensitive group advisory
People with asthma, COPD, heart disease, children, pregnant women, and adults 65+ should follow EPA AQI alerts daily and limit outdoor exertion when AQI exceeds 100. Real-time conditions: airnow.gov.
The dominant pollutant is PM2.5, driving AQI on 129 of 181 monitored days.
5-Year Air Quality Trend
Air quality is improving in Sumner County. Best year: 2024 (232 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 231 | 132 | 3 | 0 | 45 | 117 |
| 2021 | 167 | 194 | 4 | 0 | 52 | 147 |
| 2022 | 197 | 165 | 3 | 0 | 48 | 115 |
| 2023 | 179 | 182 | 3 | 1 | 51 | 152 |
| 2024 | 232 | 127 | 2 | 1 | 44 | 196 |
| 2025 | 122 | 56 | 2 | 0 | 43 | 370 |
How does Sumner County compare?
How Sumner County compares
Good-day share worse than US avg
Sumner County 67.4%
Chase County, Kansas 88.9%
US average 76.5%
Median AQI worse than US avg
Sumner County 43
Chase County, Kansas 22
US average 38
Unhealthy days / yr worse than US avg
Sumner County 1
Chase County, Kansas 0
US average 0
Other Counties in Kansas
Air quality comparison for nearby counties in Kansas.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Sumner County.
Allegan County, Michigan
AQI 43 · 71.2% good
Allen County, Ohio
AQI 43 · 65.9% good
Ashtabula County, Ohio
AQI 43 · 81.2% good
Bell County, Kentucky
AQI 43 · 63.5% good
Boise County, Idaho
AQI 43 · 72.9% good
Brazos County, Texas
AQI 43 · 63.4% good
What Sumner 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 43 means for exposure. Health guidance
- See how Sumner County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Sumner County with its Kansas neighbours before drawing a conclusion about the region. All of Kansas
Based on 181 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Sumner County, Kansas? ▼
Sumner County has a median Air Quality Index (AQI) of 43, rated "Good." 67.4% of monitored days (122 out of 181) had good air quality in 2025.
What is the main pollutant in Sumner County? ▼
The primary pollutant in Sumner County is Fine Particles (PM2.5), which was the main AQI driver on 129 days (71% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Sumner County have? ▼
In 2025, Sumner County recorded 1 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 1 Hazardous). The maximum AQI reached 370.
Is the air quality in Sumner County getting better or worse? ▼
Air quality in Sumner County is improving based on 5-year trends (2020-2025). Best year: 2024 with 232 good days. Worst year: 2025 with 122 good days.
What does AQI 43 mean for health? ▼
Sumner County's median AQI of 43 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Sumner County compare to other counties in Kansas? ▼
Sumner County has 67.4% good air days. Nearby counties in Kansas: Chase (88.9% good), Douglas (90.7% good), Ford (89.4% good), Johnson (71.8% good), Leavenworth (93.9% good), Neosho (73.5% good).
What is the 90th percentile AQI in Sumner County? ▼
The 90th percentile AQI for Sumner County is 63, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 370 (Hazardous).
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.
Every figure on PlainAir 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.