Median AQI
41
Good
Alabama · County air quality · 2025
Sumter County, Alabama
Median AQI 41 (Good). 78.0% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 78.0%
- Good-air days
- 0
- Unhealthy days
- 51%
- Cleaner than US counties
Sumter County's 2025 annual median AQI is 41 (Good), with 78.0% Good days
According to the U.S. EPA Air Quality System, Sumter County, Alabama posted a 2025 median AQI of 41 (Good) across 364 monitored days, with 78.0% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Sumter County's 78.0% Good-day share places it cleaner than 51% of US counties in 2025.
- Closest median-AQI peer
- Armstrong County (70.5% Good, median AQI 41) is the closest nationwide median-AQI peer to Sumter County.
- 2020–2025 trend
- Sumter County's floor-qualifying Good-day share is worsening from 2020 to 2025 (88.5% → 78.0%).
- Median AQI
- Median AQI: 41
The verdict
According to EPA Air Quality System monitoring data, Sumter County's air is good on balance, cleaner than the median US county, a median AQI of 41 with 78.0% of 364 monitored days in the Good band, driven mainly by PM2.5.
- 41
- median AQI · Good
- 78.0%
- days rated Good
- PM2.5
- main pollutant
- 51%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 90.
Annual release change
What changed in the 2025 EPA annual release
- Sumter County's Good-day share fell from 84.4% to 78.0% between the 2024 and 2025 EPA annual releases, a change of -6.4 percentage points.
- Sumter County's peak single-day AQI rose from 73 to 90 between the 2024 and 2025 EPA annual releases, a change of +17 points.
- Sumter County's median AQI rose from 36 to 41 between the 2024 and 2025 EPA annual releases, a change of +5 points.
Data updated August 2026
- Good · 284 d · 78.0%
- Moderate · 80 d · 22.0%
How did Sumter County's air break down in 2025?
Across 364 monitored days, 284 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 90 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 364 days monitored. Median AQI: 41 (Good).
Insights: Sumter County, Alabama. EPA monitors recorded a median Air Quality Index of 41 across 364 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 284 (78%) fell in the Good band (AQI 0–50), 80 (22%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 54, while the worst single-day peak hit 90 (Moderate). Residents averaged about 23.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (294 days), Ozone (70 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -10.4 points and the median AQI moved +8 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 90, moderate but never Unhealthy. Nearby counties show comparable readings: Baldwin (75.5% good, AQI 42); Clay (81.1% good, AQI 33); DeKalb (77.3% good, AQI 41); Elmore (97.9% good, AQI 34); Etowah (61.4% good, AQI 45); Jefferson (43.6% good, AQI 52).
Air Quality Summary
Good Days
78.0%
284 of 364 monitored days
3.0pp vs 75% target
Max AQI Recorded
90
Moderate
Health Grade
Good
90th-pct AQI 54
Sumter County, Good days share 78.0%
National avg
Share of monitored days at AQI 0-50 (Good band).
Sumter 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 364 monitored days across EPA AQI categories.
Good
284
78%
Moderate
80
22%
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 Sumter County.
- PM2.5 · 294 days · 80.8%
- Ozone · 70 days · 19.2%
Health Impact Assessment
Good
Sumter County's air quality is rated Good based on 78.0% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 78.0% 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 PM2.5, driving AQI on 294 of 364 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Sumter County. Highest Good-day share: 2020 (88.5%, 314 of 355 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 314 | 41 | 0 | 0 | 33 | 74 |
| 2021 | 311 | 44 | 0 | 0 | 35 | 71 |
| 2022 | 266 | 89 | 0 | 0 | 38 | 81 |
| 2023 | 303 | 60 | 0 | 0 | 35 | 84 |
| 2024 | 309 | 57 | 0 | 0 | 36 | 73 |
| 2025 | 284 | 80 | 0 | 0 | 41 | 90 |
How does Sumter County compare?
How Sumter County compares
Good-day share better than US avg
Sumter County 78.0%
Armstrong County, Pennsylvania 70.5%
US average 76.0%
Median AQI worse than US avg
Sumter County 41
Armstrong County, Pennsylvania 41
US average 39
Unhealthy days / yr better than US avg
Sumter County 0
Armstrong County, Pennsylvania 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Sumter County (41), not geographic neighbors.
Armstrong County, Pennsylvania
Median AQI 41 · 70.5% Good-day share
Benewah County, Idaho
Median AQI 41 · 63.4% Good-day share
Berrien County, Michigan
Median AQI 41 · 80.9% Good-day share
Callaway County, Missouri
Median AQI 41 · 89.6% Good-day share
Cambria County, Pennsylvania
Median AQI 41 · 74.5% Good-day share
Cass County, Missouri
Median AQI 41 · 77.6% 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).
Bristol City County, Virginia
78.0% Good-day share · median AQI 34
Northampton County, North Carolina
78.1% Good-day share · median AQI 33
Codington County, South Dakota
78.0% Good-day share · median AQI 35
Humboldt County, California
78.1% Good-day share · median AQI 38
McMinn County, Tennessee
78.2% Good-day share · median AQI 37
Kootenai County, Idaho
77.8% Good-day share · median AQI 31
Alabama counties on the map
Geographic containment only, other monitored counties in Alabama, independent of AQI or pollutant match.
What Sumter 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 41 means for exposure. Health guidance
- See how Sumter County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Sumter County with its Alabama neighbours before drawing a conclusion about the region. All of Alabama
Based on 364 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 Sumter County, Alabama? ▼
Sumter County has a median Air Quality Index (AQI) of 41, rated "Good." 78.0% of monitored days (284 out of 364) had good air quality in 2025.
What is the main pollutant in Sumter County? ▼
The primary pollutant in Sumter County is Fine Particles (PM2.5), which was the main AQI driver on 294 days (81% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Sumter County have? ▼
In 2025, Sumter County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 90.
Is the air quality in Sumter County getting better or worse? ▼
Air quality in Sumter County is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 88.5% (314 of 355 days). Lowest qualifying Good-day share: 2022 at 74.9% (266 of 355 days).
What does AQI 41 mean for health? ▼
Sumter County's median AQI of 41 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Sumter County compare to other counties in Alabama? ▼
Sumter County has 78.0% good air days. Nearby counties in Alabama: Baldwin (75.5% good), Clay (81.1% good), DeKalb (77.3% good), Elmore (97.9% good), Etowah (61.4% good), Jefferson (43.6% good).
What is the 90th percentile AQI in Sumter County? ▼
The 90th percentile AQI for Sumter County is 54, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 90 (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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Sumter County, Alabama · 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.