Median AQI
42
Good
Oklahoma · County air quality · 2024
Jefferson County, Oklahoma
Median AQI 42 (Good). 81.0% of monitored days rated Good, direct from EPA Air Quality System stations.
- 42
- Median AQI
- 81.0%
- Good-air days
- 0
- Unhealthy days
- 47%
- Cleaner than US counties
Jefferson County's 2024 annual median AQI is 42 (Good), with 81.0% Good days
According to the U.S. EPA Air Quality System, Jefferson County, Oklahoma posted a 2024 median AQI of 42 (Good) across 305 monitored days, with 81.0% 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
- Jefferson County's 81.0% Good-day share places it cleaner than 47% of US counties in 2024.
- Closest median-AQI peer
- Pontotoc County (71.6% Good, median AQI 43) is the closest nationwide median-AQI peer to Jefferson County.
- 2023–2024 trend
- Jefferson County's floor-qualifying Good-day share is improving from 2023 to 2024 (65.8% → 81.0%).
- Median AQI
- Median AQI: 42
The verdict
According to EPA Air Quality System monitoring data, Jefferson County's air is good on balance, more polluted than the median US county, a median AQI of 42 with 81.0% of 305 monitored days in the Good band, driven mainly by Ozone.
- 42
- median AQI · Good
- 81.0%
- days rated Good
- Ozone
- main pollutant
- 47%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 108.
Annual release change
What changed in the 2024 EPA annual release
- Jefferson County's Good-day share rose from 65.8% to 81.0% between the 2023 and 2024 EPA annual releases, a change of +15.2 percentage points.
- Jefferson County's peak single-day AQI fell from 133 to 108 between the 2023 and 2024 EPA annual releases, a change of -25 points.
- Jefferson County's median AQI fell from 46 to 42 between the 2023 and 2024 EPA annual releases, a change of -4 points.
Data updated August 2026
- Good · 247 d · 81.0%
- Moderate · 55 d · 18.0%
- USG · 3 d · 1.0%
How did Jefferson County's air break down in 2024?
Across 305 monitored days, 247 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 108 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2024). 305 days monitored. Median AQI: 42 (Good).
Insights: Jefferson County, Oklahoma. EPA monitors recorded a median Air Quality Index of 42 across 305 measured days in 2024, earning a Good classification and a Good health grade. Of those days, 247 (81%) fell in the Good band (AQI 0–50), 55 (18%) registered Moderate readings, and 3 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 61, while the worst single-day peak hit 108 (USG). Residents averaged about 24.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (305 days). Across the 2023–2024 trend window, the share of monitored days rated Good shifted by +15.2 points (measured against 231 monitored days in 2023 and 305 in 2024, so raw day counts are not comparable) and the median AQI moved -4 points, placing the multi-year trajectory at improving. The worst single reading over the 2023–2024 window was AQI 108, usg but never Unhealthy. Nearby counties show comparable readings: Adair (55.8% good, AQI 48); Canadian (79.3% good, AQI 43); Carter (81.6% good, AQI 32); Cleveland (56.9% good, AQI 48); Comanche (66.8% good, AQI 44); Creek (80.6% good, AQI 42).
Air Quality Summary
Good Days
81.0%
247 of 305 monitored days
6.0pp vs 75% target
Max AQI Recorded
108
USG
Health Grade
Good
90th-pct AQI 61
Jefferson County, Good days share 81.0%
National avg
Share of monitored days at AQI 0-50 (Good band).
Jefferson 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 (2024)
Distribution of 305 monitored days across EPA AQI categories.
Good
247
81%
Moderate
55
18%
USG
3
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Jefferson County.
- Ozone · 305 days · 100.0%
Health Impact Assessment
Good
Jefferson County's air quality is rated Good based on 81.0% good air days. No unhealthy air days were recorded in 2024.
Air quality was acceptable on 81.0% of monitored days in 2024, with a median AQI of 42. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 305 of 305 monitored days.
5-Year Air Quality Trend
Air quality is improving in Jefferson County. Highest Good-day share: 2024 (81.0%, 247 of 305 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2023 | 152 | 74 | 5 | 0 | 46 | 133 |
| 2024 | 247 | 55 | 3 | 0 | 42 | 108 |
How does Jefferson County compare?
How Jefferson County compares
Good-day share better than US avg
Jefferson County 81.0%
Pontotoc County, Oklahoma 71.6%
US average 76.0%
Median AQI worse than US avg
Jefferson County 42
Pontotoc County, Oklahoma 43
US average 39
Unhealthy days / yr better than US avg
Jefferson County 0
Pontotoc County, Oklahoma 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Jefferson County (42), not geographic neighbors.
Pontotoc County, Oklahoma
Median AQI 43 · 71.6% Good-day share
Johnston County, Oklahoma
Median AQI 44 · 74.7% Good-day share
Yancey County, North Carolina
Median AQI 44 · 81.9% Good-day share
Big Horn County, Wyoming
Median AQI 39 · 89.2% Good-day share
Chattooga County, Georgia
Median AQI 39 · 96.3% Good-day share
Weston County, Wyoming
Median AQI 39 · 87.7% Good-day share
Same primary pollutant: Ozone
Ozone 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).
Oklahoma counties on the map
Geographic containment only, other monitored counties in Oklahoma, independent of AQI or pollutant match.
What Jefferson 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 42 means for exposure. Health guidance
- See how Jefferson County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Jefferson County with its Oklahoma neighbours before drawing a conclusion about the region. All of Oklahoma
Based on 305 EPA-monitored days in 2024; 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 Jefferson County, Oklahoma? ▼
Jefferson County has a median Air Quality Index (AQI) of 42, rated "Good." 81.0% of monitored days (247 out of 305) had good air quality in 2024.
What is the main pollutant in Jefferson County? ▼
The primary pollutant in Jefferson County is Ozone (O3), which was the main AQI driver on 305 days (100% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Jefferson County have? ▼
In 2024, Jefferson County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 108.
Is the air quality in Jefferson County getting better or worse? ▼
Air quality in Jefferson County is improving across floor-qualifying years (2023-2024); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2024 at 81.0% (247 of 305 days). Lowest qualifying Good-day share: 2023 at 65.8% (152 of 231 days).
What does AQI 42 mean for health? ▼
Jefferson County's median AQI of 42 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Jefferson County compare to other counties in Oklahoma? ▼
Jefferson County has 81.0% good air days. Nearby counties in Oklahoma: Adair (55.8% good), Canadian (79.3% good), Carter (81.6% good), Cleveland (56.9% good), Comanche (66.8% good), Creek (80.6% good).
What is the 90th percentile AQI in Jefferson County? ▼
The 90th percentile AQI for Jefferson County is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 108 (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 Jefferson County, Oklahoma · 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.