EnviroNearby

Canadian County, Oklahoma air quality history

Daily Air Quality Index summaries from EPA monitors in Canadian, Oklahoma, 1999–2025.

79%
Good days in 2025
43
Median daily AQI, 2025
2
Days above 100 in 2025
276
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Canadian, Oklahoma on 276 days. 219 of those days (79%) were in the Good range, and the median daily AQI was 43. That median is about the same as the typical monitored county in Oklahoma (median 44 across 19 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 276 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 76% in 2002–2004 versus 75% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (276 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

Years with fewer than 120 monitored days (1999, 2000, 2001) are shown in the table but left out of comparisons and trend statements.

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 9 of 14 days1999: Moderate 5 of 14 days19992000: Good 28 of 56 days2000: Moderate 28 of 56 days2001: Good 30 of 57 days2001: Moderate 27 of 57 days20012002: Good 267 of 363 days2002: Moderate 72 of 363 days2002: Unhealthy for Sensitive Groups 22 of 363 days2002: Unhealthy 2 of 363 days2003: Good 262 of 365 days2003: Moderate 90 of 365 days2003: Unhealthy for Sensitive Groups 13 of 365 days20032004: Good 302 of 366 days2004: Moderate 60 of 366 days2004: Unhealthy for Sensitive Groups 4 of 366 days2005: Good 283 of 365 days2005: Moderate 68 of 365 days2005: Unhealthy for Sensitive Groups 12 of 365 days2005: Unhealthy 2 of 365 days20052006: Good 268 of 362 days2006: Moderate 70 of 362 days2006: Unhealthy for Sensitive Groups 22 of 362 days2006: Unhealthy 2 of 362 days2007: Good 316 of 365 days2007: Moderate 45 of 365 days2007: Unhealthy for Sensitive Groups 4 of 365 days20072008: Good 304 of 366 days2008: Moderate 58 of 366 days2008: Unhealthy for Sensitive Groups 4 of 366 days2009: Good 295 of 363 days2009: Moderate 64 of 363 days2009: Unhealthy for Sensitive Groups 4 of 363 days20092010: Good 310 of 365 days2010: Moderate 51 of 365 days2010: Unhealthy for Sensitive Groups 4 of 365 days2011: Good 257 of 364 days2011: Moderate 83 of 364 days2011: Unhealthy for Sensitive Groups 24 of 364 days20112012: Good 263 of 359 days2012: Moderate 81 of 359 days2012: Unhealthy for Sensitive Groups 15 of 359 days2013: Good 297 of 350 days2013: Moderate 49 of 350 days2013: Unhealthy for Sensitive Groups 4 of 350 days20132014: Good 289 of 345 days2014: Moderate 56 of 345 days2015: Good 305 of 358 days2015: Moderate 53 of 358 days20152016: Good 333 of 358 days2016: Moderate 25 of 358 days2017: Good 307 of 362 days2017: Moderate 54 of 362 days2017: Unhealthy for Sensitive Groups 1 of 362 days20172018: Good 300 of 360 days2018: Moderate 54 of 360 days2018: Unhealthy for Sensitive Groups 6 of 360 days2019: Good 306 of 355 days2019: Moderate 48 of 355 days2019: Unhealthy for Sensitive Groups 1 of 355 days20192020: Good 332 of 358 days2020: Moderate 26 of 358 days2021: Good 292 of 333 days2021: Moderate 38 of 333 days2021: Unhealthy for Sensitive Groups 3 of 333 days20212022: Good 218 of 284 days2022: Moderate 63 of 284 days2022: Unhealthy for Sensitive Groups 3 of 284 days2023: Good 195 of 278 days2023: Moderate 77 of 278 days2023: Unhealthy for Sensitive Groups 6 of 278 days20232024: Good 204 of 269 days2024: Moderate 57 of 269 days2024: Unhealthy for Sensitive Groups 8 of 269 days2025: Good 219 of 276 days2025: Moderate 55 of 276 days2025: Unhealthy for Sensitive Groups 2 of 276 days2025
  • 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 year0501001999: 90th percentile AQI 722000: 90th percentile AQI 732001: 90th percentile AQI 662002: 90th percentile AQI 902003: 90th percentile AQI 802004: 90th percentile AQI 712005: 90th percentile AQI 842006: 90th percentile AQI 932007: 90th percentile AQI 582008: 90th percentile AQI 612009: 90th percentile AQI 642010: 90th percentile AQI 612011: 90th percentile AQI 902012: 90th percentile AQI 842013: 90th percentile AQI 582014: 90th percentile AQI 612015: 90th percentile AQI 582016: 90th percentile AQI 492017: 90th percentile AQI 612018: 90th percentile AQI 642019: 90th percentile AQI 542020: 90th percentile AQI 492021: 90th percentile AQI 542022: 90th percentile AQI 672023: 90th percentile AQI 772024: 90th percentile AQI 772025: 90th percentile AQI 611999: Median AQI 482000: Median AQI 512001: Median AQI 472002: Median AQI 392003: Median AQI 402004: Median AQI 372005: Median AQI 372006: Median AQI 402007: Median AQI 352008: Median AQI 382009: Median AQI 382010: Median AQI 372011: Median AQI 422012: Median AQI 402013: Median AQI 382014: Median AQI 372015: Median AQI 372016: Median AQI 362017: Median AQI 382018: Median AQI 362019: Median AQI 372020: Median AQI 362021: Median AQI 372022: Median AQI 432023: Median AQI 452024: Median AQI 442025: Median AQI 4319992001200320052007200920112013201520172019202120232025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

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
Ozone276100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20252762195520004361115Ozone
20242692045780004477119Ozone
20232781957760004577133Ozone
20222842186330004367108Ozone
20213332923830003754126Ozone
2020358332260000364984Ozone
20193553064810003754105Ozone
20183603005460003664150Ozone
20173623075410003861105Ozone
2016358333250000364997Ozone
2015358305530000375890Ozone
20143452895600003761100Ozone
20133502974940003858112Ozone
201235926381150004084122Ozone
201136425783240004290150Ozone
20103653105140003761112Ozone
20093632956440003864122Ozone
20083663045840003861126Ozone
20073653164540003558115Ozone
200636226870222004093174Ozone
200536528368122003784172Ozone
20043663026040003771122Ozone
200336526290130004080136Ozone
200236326772222003990151Ozone
20015730270000476692PM2.5
20005628280000517387PM2.5
199914950000487273PM2.5

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 2025

All monitored counties in Oklahoma

Source: U.S. EPA AirData, “Annual AQI by County” files for 1999–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem