Median AQI
41
Good
South Carolina · County air quality · 2025
Anderson County, South Carolina
Median AQI 41 (Good). 90.0% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 90.0%
- Good-air days
- 0
- Unhealthy days
- 76%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Anderson County's air is good on balance, cleaner than most US counties, a median AQI of 41 with 90.0% of 229 monitored days in the Good band, driven mainly by Ozone.
- 41
- median AQI · Good
- 90.0%
- days rated Good
- Ozone
- main pollutant
- 76%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 84.
Data updated July 2026
- Good · 206 d · 90.0%
- Moderate · 23 d · 10.0%
How did Anderson County's air break down in 2025?
Across 229 monitored days, 206 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 84 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 229 days monitored. Median AQI: 41 (Good).
Insights: Anderson County, South Carolina. EPA monitors recorded a median Air Quality Index of 41 across 229 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 206 (90%) fell in the Good band (AQI 0–50), 23 (10%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 51, while the worst single-day peak hit 84 (Moderate). Residents averaged about 27.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (229 days). Across the 2020–2025 trend window, good days shifted by -51 and the median AQI moved +6 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 84, moderate but never Unhealthy. Nearby counties show comparable readings: Aiken (89.1% good, AQI 39); Berkeley (92.2% good, AQI 36); Charleston (59.0% good, AQI 47); Chesterfield (61.2% good, AQI 46); Darlington (87.3% good, AQI 42); Edgefield (68.1% good, AQI 44).
Air Quality Summary
Good Days
90.0%
206 of 229 monitored days
15.0pp vs 75% target
Max AQI Recorded
84
Moderate
Health Grade
Good
90th-pct AQI 51
Anderson County, Good days share 90.0%
National avg
Share of monitored days at AQI 0-50 (Good band).
Anderson 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 229 monitored days across EPA AQI categories.
Good
206
90%
Moderate
23
10%
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 Anderson County.
- Ozone · 229 days · 100.0%
Health Impact Assessment
Good
Anderson County's air quality is rated Good based on 90.0% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 90.0% of monitored days in 2025, with a median AQI of 41. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 229 of 229 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Anderson County. Best year: 2020 (257 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 257 | 8 | 0 | 0 | 35 | 71 |
| 2021 | 240 | 23 | 0 | 0 | 38 | 87 |
| 2022 | 230 | 16 | 0 | 0 | 39 | 74 |
| 2023 | 233 | 37 | 0 | 0 | 42 | 97 |
| 2024 | 213 | 41 | 1 | 0 | 43 | 115 |
| 2025 | 206 | 23 | 0 | 0 | 41 | 84 |
How does Anderson County compare?
How Anderson County compares
Good-day share better than US avg
Anderson County 90.0%
Aiken County, South Carolina 89.1%
US average 76.5%
Median AQI worse than US avg
Anderson County 41
Aiken County, South Carolina 39
US average 38
Unhealthy days / yr about average
Anderson County 0
Aiken County, South Carolina 0
US average 0
Other Counties in South Carolina
Air quality comparison for nearby counties in South Carolina.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Anderson County.
Albemarle County, Virginia
AQI 41 · 77.9% good
Berkshire County, Massachusetts
AQI 41 · 71.6% good
Berrien County, Michigan
AQI 41 · 80.9% good
Blair County, Pennsylvania
AQI 41 · 71.9% good
Bonner County, Idaho
AQI 41 · 71.3% good
Boone County, Missouri
AQI 41 · 89.1% good
What Anderson 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 41 means for exposure. Health guidance
- See how Anderson County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Anderson County with its South Carolina neighbours before drawing a conclusion about the region. All of South Carolina
Based on 229 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 Anderson County, South Carolina? ▼
Anderson County has a median Air Quality Index (AQI) of 41, rated "Good." 90.0% of monitored days (206 out of 229) had good air quality in 2025.
What is the main pollutant in Anderson County? ▼
The primary pollutant in Anderson County is Ozone (O3), which was the main AQI driver on 229 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Anderson County have? ▼
In 2025, Anderson County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 84.
Is the air quality in Anderson County getting better or worse? ▼
Air quality in Anderson County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 257 good days. Worst year: 2025 with 206 good days.
What does AQI 41 mean for health? ▼
Anderson County's median AQI of 41 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 Anderson County compare to other counties in South Carolina? ▼
Anderson County has 90.0% good air days. Nearby counties in South Carolina: Aiken (89.1% good), Berkeley (92.2% good), Charleston (59.0% good), Chesterfield (61.2% good), Darlington (87.3% good), Edgefield (68.1% good).
What is the 90th percentile AQI in Anderson County? ▼
The 90th percentile AQI for Anderson County is 51, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 84 (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.