EnviroNearby

Jefferson County, Oklahoma air quality history

Daily Air Quality Index summaries from EPA monitors in Jefferson, Oklahoma, 1999–2024.

81%
Good days in 2024
42
Median daily AQI, 2024
3
Days above 100 in 2024
305
Days with an AQI in 2024 (of 366)

In 2024, EPA reported a daily Air Quality Index (AQI) for Jefferson, Oklahoma on 305 days. 247 of those days (81%) were in the Good range, and the median daily AQI was 42. That median is lower than the typical monitored county in Oklahoma (median 45 across 20 counties), and about the same as the typical monitored U.S. county (41). The main pollutant was ozone on 305 days. Across the years with fuller monitoring, the share of Good days rose: an average of 57% in 1999–2001 versus 74% in 2018–2024.

The most recent year with data for this county is 2024; EPA's files for 2025–2025 contain no row for it, which usually means its monitors stopped reporting.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%1999: Good 91 of 165 days1999: Moderate 50 of 165 days1999: Unhealthy for Sensitive Groups 22 of 165 days1999: Unhealthy 2 of 165 days19992000: Good 165 of 274 days2000: Moderate 83 of 274 days2000: Unhealthy for Sensitive Groups 19 of 274 days2000: Unhealthy 7 of 274 days20002001: Good 117 of 206 days2001: Moderate 60 of 206 days2001: Unhealthy for Sensitive Groups 26 of 206 days2001: Unhealthy 3 of 206 days20012002: Good 181 of 263 days2002: Moderate 65 of 263 days2002: Unhealthy for Sensitive Groups 17 of 263 days20022005: Good 149 of 243 days2005: Moderate 78 of 243 days2005: Unhealthy for Sensitive Groups 14 of 243 days2005: Unhealthy 2 of 243 days20052006: Good 141 of 241 days2006: Moderate 78 of 241 days2006: Unhealthy for Sensitive Groups 18 of 241 days2006: Unhealthy 4 of 241 days20062010: Good 118 of 142 days2010: Moderate 23 of 142 days2010: Unhealthy for Sensitive Groups 1 of 142 days20102011: Good 165 of 287 days2011: Moderate 96 of 287 days2011: Unhealthy for Sensitive Groups 24 of 287 days2011: Unhealthy 2 of 287 days20112013: Good 207 of 287 days2013: Moderate 72 of 287 days2013: Unhealthy for Sensitive Groups 8 of 287 days20132014: Good 275 of 331 days2014: Moderate 54 of 331 days2014: Unhealthy for Sensitive Groups 2 of 331 days20142017: Good 207 of 246 days2017: Moderate 38 of 246 days2017: Unhealthy for Sensitive Groups 1 of 246 days20172018: Good 198 of 267 days2018: Moderate 64 of 267 days2018: Unhealthy for Sensitive Groups 4 of 267 days2018: Unhealthy 1 of 267 days20182023: Good 152 of 231 days2023: Moderate 74 of 231 days2023: Unhealthy for Sensitive Groups 5 of 231 days20232024: Good 247 of 305 days2024: Moderate 55 of 305 days2024: Unhealthy for Sensitive Groups 3 of 305 days2024
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501001501999: 90th percentile AQI 1122000: 90th percentile AQI 1002001: 90th percentile AQI 1122002: 90th percentile AQI 872005: 90th percentile AQI 932006: 90th percentile AQI 972010: 90th percentile AQI 672011: 90th percentile AQI 1002013: 90th percentile AQI 772014: 90th percentile AQI 612017: 90th percentile AQI 582018: 90th percentile AQI 712023: 90th percentile AQI 742024: 90th percentile AQI 611999: Median AQI 472000: Median AQI 462001: Median AQI 472002: Median AQI 432005: Median AQI 462006: Median AQI 472010: Median AQI 402011: Median AQI 482013: Median AQI 432014: Median AQI 412017: Median AQI 412018: Median AQI 432023: Median AQI 462024: Median AQI 4219992000200120022005200620102011201320142017201820232024
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2024

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Ozone305100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20243052475530004261108Ozone
20232311527450004674133Ozone
20182671986441004371151Ozone
20172462073810004158108Ozone
20143312755420004161133Ozone
20132872077280004377133Ozone
2011287165962420048100159Ozone
20101421182310004067119Ozone
200624114178184004797179Ozone
200524314978142004693169Ozone
200226318165170004387140Ozone
2001206117602630047112164Ozone
2000274165831970046100166Ozone
199916591502220047112156Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Oklahoma with a similar median AQI in 2024

All monitored counties in Oklahoma

Source: U.S. EPA AirData, “Annual AQI by County” files for 1999–2024 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem