Median AQI
33
Good
Alabama · County air quality · 2025
Shelby County, Alabama
Median AQI 33 (Good). 95.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 33
- Median AQI
- 95.6%
- Good-air days
- 0
- Unhealthy days
- 91%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Shelby County's air is good on balance, among the cleanest 10% of US counties, a median AQI of 33 with 95.6% of 182 monitored days in the Good band, driven mainly by Ozone.
- 33
- median AQI · Good
- 95.6%
- days rated Good
- Ozone
- main pollutant
- 91%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 80.
Data updated July 2026
- Good · 174 d · 95.6%
- Moderate · 8 d · 4.4%
How did Shelby County's air break down in 2025?
Across 182 monitored days, 174 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 80 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 182 days monitored. Median AQI: 33 (Good).
Insights: Shelby County, Alabama. EPA monitors recorded a median Air Quality Index of 33 across 182 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 174 (96%) fell in the Good band (AQI 0–50), 8 (4%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 47, while the worst single-day peak hit 80 (Moderate). Residents averaged about 28.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (182 days). Across the 2020–2025 trend window, good days shifted by -58 and the median AQI moved -1 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 80, moderate but never Unhealthy. Nearby counties show comparable readings: Baldwin (72.2% good, AQI 42); Clay (85.4% good, AQI 32); DeKalb (78.6% good, AQI 42); Elmore (97.2% good, AQI 32); Etowah (63.5% good, AQI 45); Jefferson (36.8% good, AQI 53).
Air Quality Summary
Good Days
95.6%
174 of 182 monitored days
20.6pp vs 75% target
Max AQI Recorded
80
Moderate
Health Grade
Excellent
90th-pct AQI 47
Shelby County, Good days share 95.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Shelby 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 182 monitored days across EPA AQI categories.
Good
174
96%
Moderate
8
4%
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 Shelby County.
- Ozone · 182 days · 100.0%
Health Impact Assessment
Excellent
Shelby County's air quality is rated Excellent based on 95.6% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 95.6% of monitored days in 2025, with a median AQI of 33. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 182 of 182 monitored days.
5-Year Air Quality Trend
Air quality is stable in Shelby County. Best year: 2020 (232 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 232 | 9 | 0 | 0 | 34 | 67 |
| 2021 | 231 | 12 | 0 | 0 | 35 | 77 |
| 2022 | 225 | 19 | 1 | 0 | 37 | 105 |
| 2023 | 207 | 34 | 1 | 0 | 40 | 108 |
| 2024 | 216 | 23 | 0 | 0 | 40 | 97 |
| 2025 | 174 | 8 | 0 | 0 | 33 | 80 |
How does Shelby County compare?
How Shelby County compares
Good-day share better than US avg
Shelby County 95.6%
Baldwin County, Alabama 72.2%
US average 76.5%
Median AQI better than US avg
Shelby County 33
Baldwin County, Alabama 42
US average 38
Unhealthy days / yr about average
Shelby County 0
Baldwin County, Alabama 0
US average 0
Other Counties in Alabama
Air quality comparison for nearby counties in Alabama.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Shelby County.
Ascension County, Louisiana
AQI 33 · 94.1% good
Athens County, Ohio
AQI 33 · 80.3% good
Brazoria County, Texas
AQI 33 · 84.8% good
Bristol City County, Virginia
AQI 33 · 78.3% good
Carter County, Oklahoma
AQI 33 · 80.9% good
Codington County, South Dakota
AQI 33 · 82.1% good
What Shelby 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 33 means for exposure. Health guidance
- See how Shelby County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Shelby County with its Alabama neighbours before drawing a conclusion about the region. All of Alabama
Based on 182 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 Shelby County, Alabama? ▼
Shelby County has a median Air Quality Index (AQI) of 33, rated "Good." 95.6% of monitored days (174 out of 182) had good air quality in 2025.
What is the main pollutant in Shelby County? ▼
The primary pollutant in Shelby County is Ozone (O3), which was the main AQI driver on 182 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Shelby County have? ▼
In 2025, Shelby County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 80.
Is the air quality in Shelby County getting better or worse? ▼
Air quality in Shelby County is stable based on 5-year trends (2020-2025). Best year: 2020 with 232 good days. Worst year: 2025 with 174 good days.
What does AQI 33 mean for health? ▼
Shelby County's median AQI of 33 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 Shelby County compare to other counties in Alabama? ▼
Shelby County has 95.6% good air days. Nearby counties in Alabama: Baldwin (72.2% good), Clay (85.4% good), DeKalb (78.6% good), Elmore (97.2% good), Etowah (63.5% good), Jefferson (36.8% good).
What is the 90th percentile AQI in Shelby County? ▼
The 90th percentile AQI for Shelby County is 47, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 80 (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.