Median AQI
38
Good
Indiana · County air quality · 2025
Whitley County, Indiana
Median AQI 38 (Good). 65.7% of monitored days rated Good, direct from EPA Air Quality System stations.
- 38
- Median AQI
- 65.7%
- Good-air days
- 0
- Unhealthy days
- 24%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Whitley County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 38 with 65.7% of 251 monitored days in the Good band, driven mainly by PM2.5.
- 38
- median AQI · Good
- 65.7%
- days rated Good
- PM2.5
- main pollutant
- 24%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 108.
Data updated July 2026
- Good · 165 d · 65.7%
- Moderate · 84 d · 33.5%
- USG · 2 d · 0.8%
How did Whitley County's air break down in 2025?
Across 251 monitored days, 165 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 108 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 251 days monitored. Median AQI: 38 (Good).
Insights: Whitley County, Indiana. EPA monitors recorded a median Air Quality Index of 38 across 251 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 165 (66%) fell in the Good band (AQI 0–50), 84 (33%) registered Moderate readings, and 2 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 61, while the worst single-day peak hit 108 (USG). Residents averaged about 19.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (251 days). Across the 2020–2025 trend window, good days shifted by +5 and the median AQI moved -13 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 108, usg but never Unhealthy. Nearby counties show comparable readings: Allen (58.2% good, AQI 45); Bartholomew (69.2% good, AQI 44); Boone (86.9% good, AQI 38); Brown (94.5% good, AQI 37); Carroll (87.8% good, AQI 37); Clark (59.7% good, AQI 46).
Air Quality Summary
Good Days
65.7%
165 of 251 monitored days
-9.3pp vs 75% target
Max AQI Recorded
108
USG
Health Grade
Moderate
90th-pct AQI 61
Whitley County, Good days share 65.7%
National avg
Share of monitored days at AQI 0-50 (Good band).
Whitley 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 251 monitored days across EPA AQI categories.
Good
165
66%
Moderate
84
33%
USG
2
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Whitley County.
- PM2.5 · 251 days · 100.0%
Health Impact Assessment
Moderate
Whitley County's air quality is rated Moderate based on 65.7% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 65.7% of monitored days in 2025, with a median AQI of 38. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 251 of 251 monitored days.
5-Year Air Quality Trend
Air quality is improving in Whitley County. Best year: 2024 (278 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 160 | 176 | 0 | 0 | 51 | 79 |
| 2021 | 203 | 158 | 0 | 0 | 47 | 96 |
| 2022 | 221 | 138 | 1 | 0 | 44 | 109 |
| 2023 | 195 | 161 | 4 | 2 | 48 | 223 |
| 2024 | 278 | 88 | 0 | 0 | 35 | 70 |
| 2025 | 165 | 84 | 2 | 0 | 38 | 108 |
How does Whitley County compare?
How Whitley County compares
Good-day share worse than US avg
Whitley County 65.7%
Allen County, Indiana 58.2%
US average 76.5%
Median AQI about average
Whitley County 38
Allen County, Indiana 45
US average 38
Unhealthy days / yr about average
Whitley County 0
Allen County, Indiana 0
US average 0
Other Counties in Indiana
Air quality comparison for nearby counties in Indiana.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Whitley County.
Adams County, Illinois
AQI 38 · 94.4% good
Anoka County, Minnesota
AQI 38 · 82.1% good
Atlantic County, New Jersey
AQI 38 · 79.6% good
Avery County, North Carolina
AQI 38 · 93.9% good
Barnstable County, Massachusetts
AQI 38 · 92.5% good
Bay County, Michigan
AQI 38 · 71.8% good
What Whitley County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 38 means for exposure. Health guidance
- See how Whitley County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Whitley County with its Indiana neighbours before drawing a conclusion about the region. All of Indiana
Based on 251 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 Whitley County, Indiana? ▼
Whitley County has a median Air Quality Index (AQI) of 38, rated "Good." 65.7% of monitored days (165 out of 251) had good air quality in 2025.
What is the main pollutant in Whitley County? ▼
The primary pollutant in Whitley County is Fine Particles (PM2.5), which was the main AQI driver on 251 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Whitley County have? ▼
In 2025, Whitley County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 108.
Is the air quality in Whitley County getting better or worse? ▼
Air quality in Whitley County is improving based on 5-year trends (2020-2025). Best year: 2024 with 278 good days. Worst year: 2020 with 160 good days.
What does AQI 38 mean for health? ▼
Whitley County's median AQI of 38 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 Whitley County compare to other counties in Indiana? ▼
Whitley County has 65.7% good air days. Nearby counties in Indiana: Allen (58.2% good), Bartholomew (69.2% good), Boone (86.9% good), Brown (94.5% good), Carroll (87.8% good), Clark (59.7% good).
What is the 90th percentile AQI in Whitley County? ▼
The 90th percentile AQI for Whitley County is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 108 (USG).
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.