Median AQI
41
Good
Kansas · County air quality · 2025
Trego County, Kansas
Median AQI 41 (Good). 77.2% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 77.2%
- Good-air days
- 0
- Unhealthy days
- 44%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Trego County's air is good on balance, more polluted than the median US county, a median AQI of 41 with 77.2% of 180 monitored days in the Good band, driven mainly by Ozone.
- 41
- median AQI · Good
- 77.2%
- days rated Good
- Ozone
- main pollutant
- 44%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 91.
Data updated July 2026
- Good · 139 d · 77.2%
- Moderate · 41 d · 22.8%
How did Trego County's air break down in 2025?
Across 180 monitored days, 139 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 91 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 180 days monitored. Median AQI: 41 (Good).
Insights: Trego County, Kansas. EPA monitors recorded a median Air Quality Index of 41 across 180 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 139 (77%) fell in the Good band (AQI 0–50), 41 (23%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 62, while the worst single-day peak hit 91 (Moderate). Residents averaged about 23.2 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (127 days), PM2.5 (45 days), PM10 (8 days). Across the 2020–2025 trend window, good days shifted by -168 and the median AQI moved +3 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 91, moderate but never Unhealthy. 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
77.2%
139 of 180 monitored days
2.2pp vs 75% target
Max AQI Recorded
91
Moderate
Health Grade
Good
90th-pct AQI 62
Trego County, Good days share 77.2%
National avg
Share of monitored days at AQI 0-50 (Good band).
Trego County, Unhealthy-or-worse share 0.0%
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 180 monitored days across EPA AQI categories.
Good
139
77%
Moderate
41
23%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Trego County.
- Ozone · 127 days · 70.6%
- PM2.5 · 45 days · 25.0%
- PM10 · 8 days · 4.4%
Health Impact Assessment
Good
Trego County's air quality is rated Good based on 77.2% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 77.2% of monitored days in 2025, with a median AQI of 41. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 127 of 180 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Trego County. Best year: 2020 (307 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 307 | 57 | 1 | 0 | 38 | 147 |
| 2021 | 248 | 108 | 5 | 0 | 43 | 318 |
| 2022 | 266 | 91 | 2 | 1 | 42 | 154 |
| 2023 | 211 | 149 | 4 | 1 | 47 | 164 |
| 2024 | 261 | 100 | 4 | 0 | 44 | 127 |
| 2025 | 139 | 41 | 0 | 0 | 41 | 91 |
How does Trego County compare?
How Trego County compares
Good-day share better than US avg
Trego County 77.2%
Chase County, Kansas 88.9%
US average 76.5%
Median AQI worse than US avg
Trego County 41
Chase County, Kansas 22
US average 38
Unhealthy days / yr about average
Trego County 0
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 Trego County.
Albemarle County, Virginia
AQI 41 · 77.9% good
Anderson County, South Carolina
AQI 41 · 90.0% good
Berkshire County, Massachusetts
AQI 41 · 71.6% good
Berrien County, Michigan
AQI 41 · 80.9% good
Blair County, Pennsylvania
AQI 41 · 71.9% good
Bonner County, Idaho
AQI 41 · 71.3% good
What Trego County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 41 means for exposure. Health guidance
- See how Trego County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Trego County with its Kansas neighbours before drawing a conclusion about the region. All of Kansas
Based on 180 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 Trego County, Kansas? ▼
Trego County has a median Air Quality Index (AQI) of 41, rated "Good." 77.2% of monitored days (139 out of 180) had good air quality in 2025.
What is the main pollutant in Trego County? ▼
The primary pollutant in Trego County is Ozone (O3), which was the main AQI driver on 127 days (71% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Trego County have? ▼
In 2025, Trego County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 91.
Is the air quality in Trego County getting better or worse? ▼
Air quality in Trego County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 307 good days. Worst year: 2025 with 139 good days.
What does AQI 41 mean for health? ▼
Trego County's median AQI of 41 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 Trego County compare to other counties in Kansas? ▼
Trego County has 77.2% 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 Trego County? ▼
The 90th percentile AQI for Trego County is 62, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 91 (Moderate).
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.