Median AQI
48
Good
California · County air quality · 2025
Sutter County, California
Median AQI 48 (Good). 61.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 48
- Median AQI
- 61.3%
- Good-air days
- 0
- Unhealthy days
- 17%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Sutter County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 48 with 61.3% of 212 monitored days in the Good band, driven mainly by Ozone.
- 48
- median AQI · Good
- 61.3%
- 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 100.
Data updated July 2026
- Good · 130 d · 61.3%
- Moderate · 82 d · 38.7%
How did Sutter County's air break down in 2025?
Across 212 monitored days, 130 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 100 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 212 days monitored. Median AQI: 48 (Good).
Insights: Sutter County, California. EPA monitors recorded a median Air Quality Index of 48 across 212 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 130 (61%) fell in the Good band (AQI 0–50), 82 (39%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 67, while the worst single-day peak hit 100 (Moderate). Residents averaged about 18.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (126 days), PM2.5 (86 days). Across the 2020–2025 trend window, good days shifted by -32 and the median AQI moved -5 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 100, moderate but never Unhealthy. Nearby counties show comparable readings: Amador (84.8% good, AQI 40); Butte (66.1% good, AQI 47); Calaveras (73.9% good, AQI 43); Colusa (84.9% good, AQI 39); Del Norte (81.0% good, AQI 33); El Dorado (85.8% good, AQI 39).
Air Quality Summary
Good Days
61.3%
130 of 212 monitored days
-13.7pp vs 75% target
Max AQI Recorded
100
Moderate
Health Grade
Moderate
90th-pct AQI 67
Sutter County, Good days share 61.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Sutter 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 212 monitored days across EPA AQI categories.
Good
130
61%
Moderate
82
39%
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 Sutter County.
- Ozone · 126 days · 59.4%
- PM2.5 · 86 days · 40.6%
Health Impact Assessment
Moderate
Sutter County's air quality is rated Moderate based on 61.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 61.3% of monitored days in 2025, with a median AQI of 48. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 126 of 212 monitored days.
5-Year Air Quality Trend
Air quality is improving in Sutter County. Best year: 2024 (195 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 162 | 173 | 15 | 13 | 53 | 356 |
| 2021 | 102 | 240 | 17 | 5 | 59 | 175 |
| 2022 | 154 | 205 | 5 | 0 | 52 | 119 |
| 2023 | 192 | 168 | 3 | 0 | 49 | 105 |
| 2024 | 195 | 166 | 5 | 0 | 49 | 115 |
| 2025 | 130 | 82 | 0 | 0 | 48 | 100 |
How does Sutter County compare?
How Sutter County compares
Good-day share worse than US avg
Sutter County 61.3%
Amador County, California 84.8%
US average 76.5%
Median AQI worse than US avg
Sutter County 48
Amador County, California 40
US average 38
Unhealthy days / yr about average
Sutter County 0
Amador County, California 0
US average 0
Other Counties in California
Air quality comparison for nearby counties in California.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Sutter County.
Black Hawk County, Iowa
AQI 48 · 56.6% good
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
What Sutter 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 48 means for exposure. Health guidance
- See how Sutter County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Sutter County with its California neighbours before drawing a conclusion about the region. All of California
Based on 212 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 Sutter County, California? ▼
Sutter County has a median Air Quality Index (AQI) of 48, rated "Good." 61.3% of monitored days (130 out of 212) had good air quality in 2025.
What is the main pollutant in Sutter County? ▼
The primary pollutant in Sutter County is Ozone (O3), which was the main AQI driver on 126 days (59% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Sutter County have? ▼
In 2025, Sutter County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 100.
Is the air quality in Sutter County getting better or worse? ▼
Air quality in Sutter County is improving based on 5-year trends (2020-2025). Best year: 2024 with 195 good days. Worst year: 2021 with 102 good days.
What does AQI 48 mean for health? ▼
Sutter 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 Sutter County compare to other counties in California? ▼
Sutter County has 61.3% good air days. Nearby counties in California: Amador (84.8% good), Butte (66.1% good), Calaveras (73.9% good), Colusa (84.9% good), Del Norte (81.0% good), El Dorado (85.8% good).
What is the 90th percentile AQI in Sutter County? ▼
The 90th percentile AQI for Sutter County is 67, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 100 (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.
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.