EnviroNearby

Uinta County, Wyoming air quality history

Daily Air Quality Index summaries from EPA monitors in Uinta, Wyoming, 1985–2025.

100%
Good days in 2025
9
Median daily AQI, 2025
0
Days above 100 in 2025
269
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Uinta, Wyoming on 269 days. 269 of those days (100%) were in the Good range, and the median daily AQI was 9. That median is lower than the typical monitored county in Wyoming (median 41 across 17 counties), and lower than the typical monitored U.S. county (40). The main pollutant was coarse particles (PM10) on 269 days. Across the years with fuller monitoring, the share of Good days rose: an average of 84% in 2007–2009 versus 100% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (269 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 (1985, 1986, 1987) 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%1985: Good 34 of 34 days19851986: Good 49 of 49 days1987: Good 26 of 26 days19872007: Good 267 of 365 days2007: Moderate 95 of 365 days2007: Unhealthy for Sensitive Groups 3 of 365 days2008: Good 312 of 366 days2008: Moderate 53 of 366 days2008: Unhealthy for Sensitive Groups 1 of 366 days20082009: Good 341 of 365 days2009: Moderate 24 of 365 days2010: Good 286 of 364 days2010: Moderate 76 of 364 days2010: Unhealthy for Sensitive Groups 2 of 364 days20102011: Good 322 of 365 days2011: Moderate 43 of 365 days2012: Good 254 of 366 days2012: Moderate 111 of 366 days2012: Unhealthy for Sensitive Groups 1 of 366 days20122013: Good 312 of 365 days2013: Moderate 53 of 365 days2014: Good 331 of 365 days2014: Moderate 34 of 365 days20142015: Good 316 of 365 days2015: Moderate 47 of 365 days2015: Unhealthy for Sensitive Groups 2 of 365 days2016: Good 341 of 366 days2016: Moderate 25 of 366 days20162017: Good 310 of 365 days2017: Moderate 53 of 365 days2017: Unhealthy for Sensitive Groups 1 of 365 days2017: Hazardous 1 of 365 days2018: Good 287 of 365 days2018: Moderate 77 of 365 days2018: Unhealthy for Sensitive Groups 1 of 365 days20182019: Good 315 of 365 days2019: Moderate 49 of 365 days2019: Unhealthy for Sensitive Groups 1 of 365 days2020: Good 323 of 366 days2020: Moderate 41 of 366 days2020: Unhealthy for Sensitive Groups 2 of 366 days20202021: Good 361 of 364 days2021: Moderate 3 of 364 days2022: Good 363 of 365 days2022: Moderate 2 of 365 days20222023: Good 365 of 365 days2024: Good 297 of 297 days20242025: Good 269 of 269 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 year0501001985: 90th percentile AQI 391986: 90th percentile AQI 381987: 90th percentile AQI 382007: 90th percentile AQI 712008: 90th percentile AQI 542009: 90th percentile AQI 482010: 90th percentile AQI 612011: 90th percentile AQI 512012: 90th percentile AQI 712013: 90th percentile AQI 542014: 90th percentile AQI 502015: 90th percentile AQI 542016: 90th percentile AQI 492017: 90th percentile AQI 542018: 90th percentile AQI 612019: 90th percentile AQI 582020: 90th percentile AQI 512021: 90th percentile AQI 252022: 90th percentile AQI 172023: 90th percentile AQI 122024: 90th percentile AQI 172025: 90th percentile AQI 191985: Median AQI 301986: Median AQI 191987: Median AQI 222007: Median AQI 432008: Median AQI 422009: Median AQI 402010: Median AQI 442011: Median AQI 432012: Median AQI 442013: Median AQI 442014: Median AQI 422015: Median AQI 412016: Median AQI 422017: Median AQI 442018: Median AQI 442019: Median AQI 442020: Median AQI 402021: Median AQI 72022: Median AQI 72023: Median AQI 62024: Median AQI 72025: Median AQI 9198519872008201020122014201620182020202220242025
  • 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
Coarse particles (PM10)269100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20252692690000091950PM10
20242972970000071744PM10
20233653650000061232PM10
20223653632000071755PM10
20213643613000072560PM10
20203663234120004051122Ozone
20193653154910004458101Ozone
20183652877710004461108Ozone
20173653105310014454718Ozone
2016366341250000424987Ozone
20153653164720004154101Ozone
2014365331340000425077Ozone
2013365312530000445493Ozone
201236625411110004471115Ozone
2011365322430000435190Ozone
20103642867620004461135Ozone
2009365341240000404874Ozone
20083663125310004254102Ozone
20073652679530004371108Ozone
1987262600000223840PM10
1986494900000193842PM10
1985343400000303948PM10

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 Wyoming with a similar median AQI in 2025

All monitored counties in Wyoming

Source: U.S. EPA AirData, “Annual AQI by County” files for 1985–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem