Median AQI
33
Good
Alabama · County air quality · 2025
Clay County, Alabama
Median AQI 33 (Good). 81.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 33
- Median AQI
- 81.1%
- Good-air days
- 0
- Unhealthy days
- 59%
- Cleaner than US counties
Clay County's 2025 annual median AQI is 33 (Good), with 81.1% Good days
According to the U.S. EPA Air Quality System, Clay County, Alabama posted a 2025 median AQI of 33 (Good) across 354 monitored days, with 81.1% 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
- Clay County's 81.1% Good-day share places it cleaner than 59% of US counties in 2025.
- Closest median-AQI peer
- Apache County (86.2% Good, median AQI 33) is the closest nationwide median-AQI peer to Clay County.
- 2020–2025 trend
- Clay County's floor-qualifying Good-day share is stable from 2020 to 2025 (79.0% → 81.1%).
- Median AQI
- Median AQI: 33
The verdict
According to EPA Air Quality System monitoring data, Clay County's air is good on balance, cleaner than the median US county, a median AQI of 33 with 81.1% of 354 monitored days in the Good band, driven mainly by PM2.5.
- 33
- median AQI · Good
- 81.1%
- days rated Good
- PM2.5
- main pollutant
- 59%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 133.
Annual release change
What changed in the 2025 EPA annual release
- Clay County's peak single-day AQI rose from 75 to 133 between the 2024 and 2025 EPA annual releases, a change of +58 points.
- Clay County's Good-day share fell from 86.7% to 81.1% between the 2024 and 2025 EPA annual releases, a change of -5.6 percentage points.
- Clay County's median AQI rose from 29 to 33 between the 2024 and 2025 EPA annual releases, a change of +4 points.
Data updated August 2026
- Good · 287 d · 81.1%
- Moderate · 66 d · 18.6%
- USG · 1 d · 0.3%
How did Clay County's air break down in 2025?
Across 354 monitored days, 287 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 133 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 354 days monitored. Median AQI: 33 (Good).
Insights: Clay County, Alabama. EPA monitors recorded a median Air Quality Index of 33 across 354 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 287 (81%) fell in the Good band (AQI 0–50), 66 (19%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 55, while the worst single-day peak hit 133 (USG). Residents averaged about 24.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (354 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +2.0 points (measured against 105 monitored days in 2020 and 354 in 2025, so raw day counts are not comparable) 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 133, usg but never Unhealthy. Nearby counties show comparable readings: Baldwin (75.5% good, AQI 42); DeKalb (77.3% good, AQI 41); Elmore (97.9% good, AQI 34); Etowah (61.4% good, AQI 45); Jefferson (43.6% good, AQI 52); Lawrence (91.8% good, AQI 30).
Air Quality Summary
Good Days
81.1%
287 of 354 monitored days
6.1pp vs 75% target
Max AQI Recorded
133
USG
Health Grade
Good
90th-pct AQI 55
Clay County, Good days share 81.1%
National avg
Share of monitored days at AQI 0-50 (Good band).
Clay 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 354 monitored days across EPA AQI categories.
Good
287
81%
Moderate
66
19%
USG
1
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 Clay County.
- PM2.5 · 354 days · 100.0%
Health Impact Assessment
Good
Clay County's air quality is rated Good based on 81.1% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 81.1% 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 PM2.5, driving AQI on 354 of 354 monitored days.
5-Year Air Quality Trend
Air quality is stable in Clay County. Highest Good-day share: 2024 (86.7%, 307 of 354 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 83 | 22 | 0 | 0 | 34 | 88 |
| 2021 | 87 | 23 | 0 | 0 | 36 | 70 |
| 2022 | 91 | 24 | 0 | 0 | 34 | 68 |
| 2023 | 221 | 106 | 0 | 0 | 41 | 85 |
| 2024 | 307 | 47 | 0 | 0 | 29 | 75 |
| 2025 | 287 | 66 | 1 | 0 | 33 | 133 |
How does Clay County compare?
How Clay County compares
Good-day share better than typical
Clay County 81.1%
Apache County, Arizona 86.2%
Typical US county 76.0%
Median AQI better than typical
Clay County 33
Apache County, Arizona 33
Typical US county 39
Unhealthy days / yr better than typical
Clay County 0
Apache County, Arizona 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Clay County (33), not geographic neighbors.
Apache County, Arizona
Median AQI 33 · 86.2% Good-day share
Ascension County, Louisiana
Median AQI 33 · 95.6% Good-day share
Carlton County, Minnesota
Median AQI 33 · 82.8% Good-day share
Clark County, Illinois
Median AQI 33 · 93.8% Good-day share
Clark County, Washington
Median AQI 33 · 82.7% Good-day share
Denali County, Alaska
Median AQI 33 · 99.7% 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).
Swain County, North Carolina
81.1% Good-day share · median AQI 37
Albemarle County, Virginia
81.0% Good-day share · median AQI 38
New London County, Connecticut
81.3% Good-day share · median AQI 38
Virginia Beach City County, Virginia
80.8% Good-day share · median AQI 34
Walla Walla County, Washington
80.8% Good-day share · median AQI 28
Chesterfield County, Virginia
80.8% Good-day share · median AQI 39
Alabama counties on the map
Geographic containment only, other monitored counties in Alabama, independent of AQI or pollutant match.
What Clay 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 33 means for exposure. Health guidance
- See how Clay County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Clay County with its Alabama neighbours before drawing a conclusion about the region. All of Alabama
Based on 354 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 Clay County, Alabama? ▼
Clay County has a median Air Quality Index (AQI) of 33, rated "Good." 81.1% of monitored days (287 out of 354) had good air quality in 2025.
What is the main pollutant in Clay County? ▼
The primary pollutant in Clay County is Fine Particles (PM2.5), which was the main AQI driver on 354 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Clay County have? ▼
In 2025, Clay County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 133.
Is the air quality in Clay County getting better or worse? ▼
Air quality in Clay County is stable across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2024 at 86.7% (307 of 354 days). Lowest qualifying Good-day share: 2023 at 67.6% (221 of 327 days).
What does AQI 33 mean for health? ▼
Clay County's median AQI of 33 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Clay County compare to other counties in Alabama? ▼
Clay County has 81.1% good air days. Nearby counties in Alabama: Baldwin (75.5% good), DeKalb (77.3% good), Elmore (97.9% good), Etowah (61.4% good), Jefferson (43.6% good), Lawrence (91.8% good).
What is the 90th percentile AQI in Clay County? ▼
The 90th percentile AQI for Clay County is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 133 (USG).
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 Clay 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.