Kansas · County air quality · 2025
Sumner County, Kansas
Median AQI 45 (Good). 65.8% of monitored days rated Good, direct from EPA Air Quality System stations.
- 45
- Median AQI
- 65.8%
- Good-air days
- 1
- Unhealthy days
- 24%
- Cleaner than US counties
Sumner County's 2025 annual median AQI is 45 (Good), with 65.8% Good days
According to the U.S. EPA Air Quality System, Sumner County, Kansas posted a 2025 median AQI of 45 (Good) across 365 monitored days, with 65.8% 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
- Sumner County's 65.8% Good-day share places it cleaner than 24% 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 Sumner County.
- 2020–2025 trend
- Sumner County's floor-qualifying Good-day share is stable from 2020 to 2025 (63.1% → 65.9%).
- Median AQI
- Median AQI: 45
According to the 2025 EPA AQS county release on PlainAirData, Sumner County, Kansas ranks #750 of 951 by median AQI (45) and #721 by good-day share (65.8%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.
Annual release change
What changed in the 2025 EPA annual release
- Sumner County's peak single-day AQI rose from 196 to 370 between the 2024 and 2025 EPA annual releases, a change of +174 points.
- Sumner County's Good-day share rose from 64.1% to 65.8% between the 2024 and 2025 EPA annual releases, a change of +1.7 percentage points.
- Sumner County's Unhealthy-category days fell from 1 to 0 between the 2024 and 2025 EPA annual releases, a change of -1 days.
Data updated August 2026
- Good · 240 d · 65.8%
- Moderate · 121 d · 33.2%
- USG · 3 d · 0.8%
- Hazardous · 1 d · 0.3%
How did Sumner County's air break down in 2025?
Across 365 monitored days, 240 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 →Share of monitored days at AQI 0-50 (Good band).
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
Where Sumner County sits nationally
COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Sumner County's Good-day share is 65.8% - cleaner than 24% of that comparison set.
Sumner County Good-day share vs. every US county
Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
65.8% 24th percentile higher than 24% of 951 US counties
Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Sumner County.
- PM2.5 · 229 days · 62.7%
- Ozone · 112 days · 30.7%
- PM10 · 24 days · 6.6%
2024 daily-monitor rhythm in Sumner County
Month-by-month median AQI from EPA day-level county monitors (362 reported days in 2024). Oct posted the highest typical readings (median AQI 57, peak 80); Nov was cleanest at median 25. Summer months (Jun–Aug) averaged median AQI 47 vs 37 in Dec–Feb. 1 day crossed Unhealthy (AQI >150) at least once that year.
Five-year seasonal record
EPA day-level county files · 2020–20241,823 daily readings show a recurring local pattern: Jun has the highest matched-month median AQI (54), while Dec is lowest (40). Each cell is that month’s median daily AQI, not a current-air forecast.
Lower AQI is better. The colors summarize EPA AQI bands; gaps mean the county had no day-level record for that month.
Health Impact Assessment
Sumner County's air quality is rated Moderate based on 65.8% 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 229 of 365 monitored days.
5-Year Air Quality Trend
Air quality is stable in Sumner County. Highest Good-day share: 2025 (65.9%, 240 of 365 monitored 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 | 240 | 121 | 3 | 0 | 45 | 370 |
How does Sumner County compare?
How Sumner County compares
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 Sumner County, Kansas · 2020–2025
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.