Median AQI
46
Good
Indiana · County air quality · 2025
Howard County, Indiana
Median AQI 46 (Good). 61.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 46
- Median AQI
- 61.5%
- Good-air days
- 0
- Unhealthy days
- 17%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Howard County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 46 with 61.5% of 270 monitored days in the Good band, driven mainly by Ozone.
- 46
- median AQI · Good
- 61.5%
- days rated Good
- Ozone
- main pollutant
- 17%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 122.
Data updated July 2026
- Good · 166 d · 61.5%
- Moderate · 101 d · 37.4%
- USG · 3 d · 1.1%
How did Howard County's air break down in 2025?
Across 270 monitored days, 166 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 122 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 270 days monitored. Median AQI: 46 (Good).
Insights: Howard County, Indiana. EPA monitors recorded a median Air Quality Index of 46 across 270 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 166 (61%) fell in the Good band (AQI 0–50), 101 (37%) registered Moderate readings, and 3 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 64, while the worst single-day peak hit 122 (USG). Residents averaged about 18.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (142 days), PM2.5 (128 days). Across the 2020–2025 trend window, good days shifted by -100 and the median AQI moved +4 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 122, 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
61.5%
166 of 270 monitored days
-13.5pp vs 75% target
Max AQI Recorded
122
USG
Health Grade
Moderate
90th-pct AQI 64
Howard County, Good days share 61.5%
National avg
Share of monitored days at AQI 0-50 (Good band).
Howard 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 270 monitored days across EPA AQI categories.
Good
166
61%
Moderate
101
37%
USG
3
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 Howard County.
- Ozone · 142 days · 52.6%
- PM2.5 · 128 days · 47.4%
Health Impact Assessment
Moderate
Howard County's air quality is rated Moderate based on 61.5% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 61.5% of monitored days in 2025, with a median AQI of 46. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 142 of 270 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Howard County. Best year: 2020 (266 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 266 | 99 | 1 | 0 | 42 | 108 |
| 2021 | 227 | 132 | 2 | 0 | 44 | 105 |
| 2022 | 246 | 114 | 4 | 0 | 44 | 108 |
| 2023 | 234 | 119 | 10 | 2 | 45 | 199 |
| 2024 | 241 | 125 | 0 | 0 | 44 | 93 |
| 2025 | 166 | 101 | 3 | 0 | 46 | 122 |
How does Howard County compare?
How Howard County compares
Good-day share worse than US avg
Howard County 61.5%
Allen County, Indiana 58.2%
US average 76.5%
Median AQI worse than US avg
Howard County 46
Allen County, Indiana 45
US average 38
Unhealthy days / yr about average
Howard 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 Howard County.
Bay County, Florida
AQI 46 · 60.6% good
Blount County, Tennessee
AQI 46 · 69.6% good
Cache County, Utah
AQI 46 · 61.2% good
Chesterfield County, South Carolina
AQI 46 · 61.2% good
Clark County, Indiana
AQI 46 · 59.7% good
Clark County, Ohio
AQI 46 · 59.4% good
What Howard 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 46 means for exposure. Health guidance
- See how Howard County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Howard County with its Indiana neighbours before drawing a conclusion about the region. All of Indiana
Based on 270 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 Howard County, Indiana? ▼
Howard County has a median Air Quality Index (AQI) of 46, rated "Good." 61.5% of monitored days (166 out of 270) had good air quality in 2025.
What is the main pollutant in Howard County? ▼
The primary pollutant in Howard County is Ozone (O3), which was the main AQI driver on 142 days (53% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Howard County have? ▼
In 2025, Howard County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 122.
Is the air quality in Howard County getting better or worse? ▼
Air quality in Howard County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 266 good days. Worst year: 2025 with 166 good days.
What does AQI 46 mean for health? ▼
Howard County's median AQI of 46 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 Howard County compare to other counties in Indiana? ▼
Howard County has 61.5% 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 Howard County? ▼
The 90th percentile AQI for Howard County is 64, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 122 (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.