Median AQI
48
Good
Iowa · County air quality · 2025
Black Hawk County, Iowa
Median AQI 48 (Good). 56.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 48
- Median AQI
- 56.6%
- Good-air days
- 1
- Unhealthy days
- 11%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Black Hawk County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 48 with 56.6% of 304 monitored days in the Good band, driven mainly by PM2.5.
- 48
- median AQI · Good
- 56.6%
- days rated Good
- PM2.5
- main pollutant
- 11%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 158.
Data updated July 2026
- Good · 172 d · 56.6%
- Moderate · 130 d · 42.8%
- USG · 1 d · 0.3%
- Unhealthy · 1 d · 0.3%
How did Black Hawk County's air break down in 2025?
Across 304 monitored days, 172 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 158 (Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 304 days monitored. Median AQI: 48 (Good).
Insights: Black Hawk County, Iowa. EPA monitors recorded a median Air Quality Index of 48 across 304 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 172 (57%) fell in the Good band (AQI 0–50), 130 (43%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 64, while the worst single-day peak hit 158 (Unhealthy). Residents averaged about 17.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (304 days). Across the 2020–2025 trend window, good days shifted by -67 and the median AQI moved +6 points, placing the multi-year trajectory at worsening. Residents and visitors experienced 1 unhealthy-or-worse days combined, periods when the EPA recommends sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Bremer (87.1% good, AQI 38); Clinton (59.9% good, AQI 45); Harrison (83.0% good, AQI 39); Johnson (71.0% good, AQI 36); Linn (61.2% good, AQI 44); Montgomery (68.8% good, AQI 43).
Air Quality Summary
Good Days
56.6%
172 of 304 monitored days
-18.4pp vs 75% target
Max AQI Recorded
158
Unhealthy
Health Grade
Moderate
90th-pct AQI 64
Black Hawk County, Good days share 56.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Black Hawk County, Unhealthy-or-worse share 0.3%
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 304 monitored days across EPA AQI categories.
Good
172
57%
Moderate
130
43%
USG
1
0%
Unhealthy
1
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Black Hawk County.
- PM2.5 · 304 days · 100.0%
Health Impact Assessment
Moderate
Black Hawk County's air quality is rated Moderate based on 56.6% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 1 days reached "Unhealthy for Sensitive Groups" (AQI 101-150) and peak AQI reached 158. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 304 of 304 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Black Hawk County. Best year: 2020 (239 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 239 | 127 | 0 | 0 | 42 | 92 |
| 2021 | 211 | 154 | 0 | 0 | 47 | 96 |
| 2022 | 232 | 132 | 0 | 0 | 44 | 84 |
| 2023 | 147 | 200 | 4 | 3 | 53 | 187 |
| 2024 | 215 | 150 | 0 | 0 | 47 | 87 |
| 2025 | 172 | 130 | 1 | 1 | 48 | 158 |
How does Black Hawk County compare?
How Black Hawk County compares
Good-day share worse than US avg
Black Hawk County 56.6%
Bremer County, Iowa 87.1%
US average 76.5%
Median AQI worse than US avg
Black Hawk County 48
Bremer County, Iowa 38
US average 38
Unhealthy days / yr worse than US avg
Black Hawk County 1
Bremer County, Iowa 0
US average 0
Other Counties in Iowa
Air quality comparison for nearby counties in Iowa.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Black Hawk County.
Box Elder County, Utah
AQI 48 · 60.0% good
Brookings County, South Dakota
AQI 48 · 53.0% good
Clear Creek County, Colorado
AQI 48 · 64.4% good
Coconino County, Arizona
AQI 48 · 62.5% good
Columbia County, Florida
AQI 48 · 56.4% good
Davis County, Utah
AQI 48 · 59.5% good
What Black Hawk County's air means for you
On most days the air here is fine, but PM2.5 drives 1 unhealthy-or-worse day a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 48 means for exposure. Health guidance
- See how Black Hawk County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Black Hawk County with its Iowa neighbours before drawing a conclusion about the region. All of Iowa
Based on 304 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 Black Hawk County, Iowa? ▼
Black Hawk County has a median Air Quality Index (AQI) of 48, rated "Good." 56.6% of monitored days (172 out of 304) had good air quality in 2025.
What is the main pollutant in Black Hawk County? ▼
The primary pollutant in Black Hawk County is Fine Particles (PM2.5), which was the main AQI driver on 304 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Black Hawk County have? ▼
In 2025, Black Hawk County recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 158.
Is the air quality in Black Hawk County getting better or worse? ▼
Air quality in Black Hawk County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 239 good days. Worst year: 2023 with 147 good days.
What does AQI 48 mean for health? ▼
Black Hawk County's median AQI of 48 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 Black Hawk County compare to other counties in Iowa? ▼
Black Hawk County has 56.6% good air days. Nearby counties in Iowa: Bremer (87.1% good), Clinton (59.9% good), Harrison (83.0% good), Johnson (71.0% good), Linn (61.2% good), Montgomery (68.8% good).
What is the 90th percentile AQI in Black Hawk County? ▼
The 90th percentile AQI for Black Hawk County is 64, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 158 (Unhealthy).
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.