Median AQI
46
Good
Iowa · County air quality · 2025
Scott County, Iowa
Median AQI 46 (Good). 58.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 46
- Median AQI
- 58.9%
- Good-air days
- 1
- Unhealthy days
- 14%
- Cleaner than US counties
Scott County's 2025 annual median AQI is 46 (Good), with 58.9% Good days
According to the U.S. EPA Air Quality System, Scott County, Iowa posted a 2025 median AQI of 46 (Good) across 365 monitored days, with 58.9% rated Good and 1 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Scott County's 58.9% Good-day share places it cleaner than 14% of US counties in 2025.
- Closest median-AQI peer
- Beaver County (55.6% Good, median AQI 46) is the closest nationwide median-AQI peer to Scott County.
- 2020–2025 trend
- Scott County's floor-qualifying Good-day share is improving from 2020 to 2025 (47.3% → 58.9%).
- Median AQI
- Median AQI: 46
The verdict
According to EPA Air Quality System monitoring data, Scott County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 46 with 58.9% of 365 monitored days in the Good band, driven mainly by PM2.5.
- 46
- median AQI · Good
- 58.9%
- days rated Good
- PM2.5
- main pollutant
- 14%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 159.
Annual release change
What changed in the 2025 EPA annual release
- Scott County's peak single-day AQI rose from 90 to 159 between the 2024 and 2025 EPA annual releases, a change of +69 points.
- Scott County's Good-day share fell from 61.2% to 58.9% between the 2024 and 2025 EPA annual releases, a change of -2.3 percentage points.
- Scott County's Unhealthy-category days rose from 0 to 1 between the 2024 and 2025 EPA annual releases, a change of +1 days.
Data updated August 2026
- Good · 215 d · 58.9%
- Moderate · 148 d · 40.5%
- USG · 1 d · 0.3%
- Unhealthy · 1 d · 0.3%
How did Scott County's air break down in 2025?
Across 365 monitored days, 215 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 159 (Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 365 days monitored. Median AQI: 46 (Good).
Insights: Scott County, Iowa. EPA monitors recorded a median Air Quality Index of 46 across 365 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 215 (59%) fell in the Good band (AQI 0–50), 148 (41%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 71, while the worst single-day peak hit 159 (Unhealthy). Residents averaged about 17.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (155 days), Ozone (149 days), PM10 (61 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +11.6 points and the median AQI moved -6 points, placing the multi-year trajectory at improving. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Black Hawk (53.4% good, AQI 49); Bremer (87.1% good, AQI 38); Clinton (59.5% good, AQI 45); Harrison (83.0% good, AQI 39); Johnson (70.1% good, AQI 37); Linn (61.4% good, AQI 44).
Air Quality Summary
Good Days
58.9%
215 of 365 monitored days
-16.1pp vs 75% target
Max AQI Recorded
159
Unhealthy
Health Grade
Moderate
90th-pct AQI 71
Scott County, Good days share 58.9%
National avg
Share of monitored days at AQI 0-50 (Good band).
Scott County, Unhealthy-or-worse share 2.7%
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
215
59%
Moderate
148
41%
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 Scott County.
- PM2.5 · 155 days · 42.5%
- Ozone · 149 days · 40.8%
- PM10 · 61 days · 16.7%
Health Impact Assessment
Moderate
Scott County's air quality is rated Moderate based on 58.9% 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 159. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 155 of 365 monitored days.
5-Year Air Quality Trend
Air quality is improving in Scott County. Highest Good-day share: 2024 (61.2%, 224 of 366 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 173 | 190 | 2 | 1 | 52 | 156 |
| 2021 | 145 | 219 | 1 | 0 | 53 | 102 |
| 2022 | 202 | 163 | 0 | 0 | 49 | 96 |
| 2023 | 142 | 200 | 19 | 3 | 53 | 219 |
| 2024 | 224 | 142 | 0 | 0 | 46 | 90 |
| 2025 | 215 | 148 | 1 | 1 | 46 | 159 |
How does Scott County compare?
How Scott County compares
Good-day share worse than typical
Scott County 58.9%
Beaver County, Pennsylvania 55.6%
Typical US county 76.0%
Median AQI worse than typical
Scott County 46
Beaver County, Pennsylvania 46
Typical US county 39
Unhealthy days / yr about typical
Scott County 1
Beaver County, Pennsylvania 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Scott County (46), not geographic neighbors.
Beaver County, Pennsylvania
Median AQI 46 · 55.6% Good-day share
Brookings County, South Dakota
Median AQI 46 · 58.6% Good-day share
Buchanan County, Missouri
Median AQI 46 · 56.4% Good-day share
Butte County, California
Median AQI 46 · 65.2% Good-day share
Clark County, Indiana
Median AQI 46 · 58.1% Good-day share
Clarke County, Georgia
Median AQI 46 · 57.8% 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).
Chatham County, Georgia
58.6% Good-day share · median AQI 47
Bronx County, New York
59.2% Good-day share · median AQI 45
Webster County, Iowa
59.2% Good-day share · median AQI 45
DeKalb County, Georgia
58.4% Good-day share · median AQI 47
Saint Clair County, Illinois
58.4% Good-day share · median AQI 47
Yolo County, California
58.4% Good-day share · median AQI 47
Iowa counties on the map
Geographic containment only, other monitored counties in Iowa, independent of AQI or pollutant match.
What Scott 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 46 means for exposure. Health guidance
- See how Scott County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Scott County with its Iowa neighbours before drawing a conclusion about the region. All of Iowa
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 Scott County, Iowa? ▼
Scott County has a median Air Quality Index (AQI) of 46, rated "Good." 58.9% of monitored days (215 out of 365) had good air quality in 2025.
What is the main pollutant in Scott County? ▼
The primary pollutant in Scott County is Fine Particles (PM2.5), which was the main AQI driver on 155 days (42% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Scott County have? ▼
In 2025, Scott County recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 159.
Is the air quality in Scott County getting better or worse? ▼
Air quality in Scott County is improving across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2024 at 61.2% (224 of 366 days). Lowest qualifying Good-day share: 2023 at 39.0% (142 of 365 days).
What does AQI 46 mean for health? ▼
Scott County's median AQI of 46 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Scott County compare to other counties in Iowa? ▼
Scott County has 58.9% good air days. Nearby counties in Iowa: Black Hawk (53.4% good), Bremer (87.1% good), Clinton (59.5% good), Harrison (83.0% good), Johnson (70.1% good), Linn (61.4% good).
What is the 90th percentile AQI in Scott County? ▼
The 90th percentile AQI for Scott County is 71, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 159 (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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Scott County, Iowa · 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.