Median AQI
49
Good
South Carolina · County air quality · 2025
Spartanburg County, South Carolina
Median AQI 49 (Good). 52.4% of monitored days rated Good, direct from EPA Air Quality System stations.
- 49
- Median AQI
- 52.4%
- Good-air days
- 0
- Unhealthy days
- 8%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Spartanburg County's air is good on balance, among the most polluted counties nationally, a median AQI of 49 with 52.4% of 273 monitored days in the Good band, driven mainly by PM2.5.
- 49
- median AQI · Good
- 52.4%
- days rated Good
- PM2.5
- main pollutant
- 8%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 93.
Data updated July 2026
- Good · 143 d · 52.4%
- Moderate · 130 d · 47.6%
How did Spartanburg County's air break down in 2025?
Across 273 monitored days, 143 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 93 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 273 days monitored. Median AQI: 49 (Good).
Insights: Spartanburg County, South Carolina. EPA monitors recorded a median Air Quality Index of 49 across 273 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 143 (52%) fell in the Good band (AQI 0–50), 130 (48%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 62, while the worst single-day peak hit 93 (Moderate). Residents averaged about 15.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (165 days), Ozone (108 days). Across the 2020–2025 trend window, good days shifted by -89 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 93, moderate but never Unhealthy. Nearby counties show comparable readings: Aiken (89.1% good, AQI 39); Anderson (90.0% good, AQI 41); Berkeley (92.2% good, AQI 36); Charleston (59.0% good, AQI 47); Chesterfield (61.2% good, AQI 46); Darlington (87.3% good, AQI 42).
Air Quality Summary
Good Days
52.4%
143 of 273 monitored days
-22.6pp vs 75% target
Max AQI Recorded
93
Moderate
Health Grade
Moderate
90th-pct AQI 62
Spartanburg County, Good days share 52.4%
National avg
Share of monitored days at AQI 0-50 (Good band).
Spartanburg 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 273 monitored days across EPA AQI categories.
Good
143
52%
Moderate
130
48%
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 Spartanburg County.
- PM2.5 · 165 days · 60.4%
- Ozone · 108 days · 39.6%
Health Impact Assessment
Moderate
Spartanburg County's air quality is rated Moderate based on 52.4% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 52.4% of monitored days in 2025, with a median AQI of 49. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 165 of 273 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Spartanburg County. Best year: 2020 (232 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 232 | 132 | 2 | 0 | 45 | 112 |
| 2021 | 201 | 152 | 1 | 0 | 46 | 119 |
| 2022 | 206 | 157 | 0 | 0 | 47 | 87 |
| 2023 | 166 | 194 | 5 | 0 | 51 | 136 |
| 2024 | 188 | 171 | 4 | 0 | 49 | 112 |
| 2025 | 143 | 130 | 0 | 0 | 49 | 93 |
How does Spartanburg County compare?
How Spartanburg County compares
Good-day share worse than US avg
Spartanburg County 52.4%
Aiken County, South Carolina 89.1%
US average 76.5%
Median AQI worse than US avg
Spartanburg County 49
Aiken County, South Carolina 39
US average 38
Unhealthy days / yr about average
Spartanburg 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 Spartanburg County.
Allegheny County, Pennsylvania
AQI 49 · 51.6% good
Arkansas County, Arkansas
AQI 49 · 51.6% good
Ashley County, Arkansas
AQI 49 · 53.9% good
Clayton County, Georgia
AQI 49 · 53.1% good
Cleveland County, Oklahoma
AQI 49 · 53.7% good
Dewey County, Oklahoma
AQI 49 · 56.6% good
What Spartanburg County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 49 means for exposure. Health guidance
- See how Spartanburg County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Spartanburg County with its South Carolina neighbours before drawing a conclusion about the region. All of South Carolina
Based on 273 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 Spartanburg County, South Carolina? ▼
Spartanburg County has a median Air Quality Index (AQI) of 49, rated "Good." 52.4% of monitored days (143 out of 273) had good air quality in 2025.
What is the main pollutant in Spartanburg County? ▼
The primary pollutant in Spartanburg County is Fine Particles (PM2.5), which was the main AQI driver on 165 days (60% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Spartanburg County have? ▼
In 2025, Spartanburg County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 93.
Is the air quality in Spartanburg County getting better or worse? ▼
Air quality in Spartanburg County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 232 good days. Worst year: 2025 with 143 good days.
What does AQI 49 mean for health? ▼
Spartanburg County's median AQI of 49 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 Spartanburg County compare to other counties in South Carolina? ▼
Spartanburg County has 52.4% good air days. Nearby counties in South Carolina: Aiken (89.1% good), Anderson (90.0% good), Berkeley (92.2% good), Charleston (59.0% good), Chesterfield (61.2% good), Darlington (87.3% good).
What is the 90th percentile AQI in Spartanburg County? ▼
The 90th percentile AQI for Spartanburg County is 62, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 93 (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.