Median AQI
37
Good
Indiana · County air quality · 2025
Henry County, Indiana
Median AQI 37 (Good). 69.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 37
- Median AQI
- 69.9%
- Good-air days
- 0
- Unhealthy days
- 32%
- Cleaner than US counties
Henry County's 2025 annual median AQI is 37 (Good), with 69.9% Good days
According to the U.S. EPA Air Quality System, Henry County, Indiana posted a 2025 median AQI of 37 (Good) across 365 monitored days, with 69.9% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Henry County's 69.9% Good-day share places it cleaner than 32% of US counties in 2025.
- Closest median-AQI peer
- Alachua County (88.7% Good, median AQI 37) is the closest nationwide median-AQI peer to Henry County.
- 2020–2025 trend
- Henry County's floor-qualifying Good-day share is worsening from 2020 to 2025 (73.7% → 69.9%).
- Median AQI
- Median AQI: 37
The verdict
According to EPA Air Quality System monitoring data, Henry County's air is good on balance, more polluted than the median US county, a median AQI of 37 with 69.9% of 365 monitored days in the Good band, driven mainly by PM2.5.
- 37
- median AQI · Good
- 69.9%
- days rated Good
- PM2.5
- main pollutant
- 32%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 95.
Annual release change
What changed in the 2025 EPA annual release
- Henry County's Good-day share fell from 78.1% to 69.9% between the 2024 and 2025 EPA annual releases, a change of -8.3 percentage points.
- Henry County's peak single-day AQI rose from 75 to 95 between the 2024 and 2025 EPA annual releases, a change of +20 points.
- Henry County's median AQI rose from 34 to 37 between the 2024 and 2025 EPA annual releases, a change of +3 points.
Data updated August 2026
- Good · 255 d · 69.9%
- Moderate · 110 d · 30.1%
How did Henry County's air break down in 2025?
Across 365 monitored days, 255 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 95 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 365 days monitored. Median AQI: 37 (Good).
Insights: Henry County, Indiana. EPA monitors recorded a median Air Quality Index of 37 across 365 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 255 (70%) fell in the Good band (AQI 0–50), 110 (30%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 59, while the worst single-day peak hit 95 (Moderate). Residents averaged about 21.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (365 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -3.9 points (measured against 118 monitored days in 2020 and 365 in 2025, so raw day counts are not comparable) and the median AQI moved -2 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 95, moderate but never Unhealthy. Nearby counties show comparable readings: Allen (60.0% good, AQI 44); Bartholomew (72.6% good, AQI 43); Boone (89.7% good, AQI 35); Brown (95.9% good, AQI 34); Carroll (90.8% good, AQI 35); Clark (58.1% good, AQI 46).
Air Quality Summary
Good Days
69.9%
255 of 365 monitored days
-5.1pp vs 75% target
Max AQI Recorded
95
Moderate
Health Grade
Moderate
90th-pct AQI 59
Henry County, Good days share 69.9%
National avg
Share of monitored days at AQI 0-50 (Good band).
Henry 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 365 monitored days across EPA AQI categories.
Good
255
70%
Moderate
110
30%
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 Henry County.
- PM2.5 · 365 days · 100.0%
Health Impact Assessment
Moderate
Henry County's air quality is rated Moderate based on 69.9% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 69.9% of monitored days in 2025, with a median AQI of 37. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 365 of 365 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Henry County. Highest Good-day share: 2022 (78.4%, 87 of 111 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 87 | 31 | 0 | 0 | 39 | 67 |
| 2021 | 78 | 39 | 0 | 0 | 38 | 82 |
| 2022 | 87 | 24 | 0 | 0 | 34 | 95 |
| 2023 | 214 | 124 | 8 | 2 | 44 | 192 |
| 2024 | 282 | 79 | 0 | 0 | 34 | 75 |
| 2025 | 255 | 110 | 0 | 0 | 37 | 95 |
How does Henry County compare?
How Henry County compares
Good-day share worse than typical
Henry County 69.9%
Alachua County, Florida 88.7%
Typical US county 76.0%
Median AQI better than typical
Henry County 37
Alachua County, Florida 37
Typical US county 39
Unhealthy days / yr better than typical
Henry County 0
Alachua County, Florida 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Henry County (37), not geographic neighbors.
Alachua County, Florida
Median AQI 37 · 88.7% Good-day share
Arlington County, Virginia
Median AQI 37 · 87.4% Good-day share
Bennington County, Vermont
Median AQI 37 · 83.6% Good-day share
Boone County, Missouri
Median AQI 37 · 93.2% Good-day share
Bradford County, Pennsylvania
Median AQI 37 · 81.6% Good-day share
Brown County, Wisconsin
Median AQI 37 · 73.2% 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).
Hancock County, West Virginia
69.9% Good-day share · median AQI 42
Jackson County, Mississippi
69.9% Good-day share · median AQI 44
Dubois County, Indiana
69.7% Good-day share · median AQI 39
Floyd County, Georgia
69.7% Good-day share · median AQI 38
Chelan County, Washington
69.6% Good-day share · median AQI 35
Pinellas County, Florida
69.6% Good-day share · median AQI 44
Indiana counties on the map
Geographic containment only, other monitored counties in Indiana, independent of AQI or pollutant match.
What Henry 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 37 means for exposure. Health guidance
- See how Henry County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Henry County with its Indiana neighbours before drawing a conclusion about the region. All of Indiana
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 Henry County, Indiana? ▼
Henry County has a median Air Quality Index (AQI) of 37, rated "Good." 69.9% of monitored days (255 out of 365) had good air quality in 2025.
What is the main pollutant in Henry County? ▼
The primary pollutant in Henry County is Fine Particles (PM2.5), which was the main AQI driver on 365 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Henry County have? ▼
In 2025, Henry County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 95.
Is the air quality in Henry County getting better or worse? ▼
Air quality in Henry 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: 2022 at 78.4% (87 of 111 days). Lowest qualifying Good-day share: 2023 at 61.5% (214 of 348 days).
What does AQI 37 mean for health? ▼
Henry County's median AQI of 37 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Henry County compare to other counties in Indiana? ▼
Henry County has 69.9% good air days. Nearby counties in Indiana: Allen (60.0% good), Bartholomew (72.6% good), Boone (89.7% good), Brown (95.9% good), Carroll (90.8% good), Clark (58.1% good).
What is the 90th percentile AQI in Henry County? ▼
The 90th percentile AQI for Henry County is 59, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 95 (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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Henry County, Indiana · 2020–2025
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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.