EnviroNearby

Rio Blanco County, Colorado air quality history

Daily Air Quality Index summaries from EPA monitors in Rio Blanco, Colorado, 2010–2024.

73%
Good days in 2024
46
Median daily AQI, 2024
4
Days above 100 in 2024
366
Days with an AQI in 2024 (of 366)

In 2024, EPA reported a daily Air Quality Index (AQI) for Rio Blanco, Colorado on 366 days. 266 of those days (73%) were in the Good range, and the median daily AQI was 46. That median is about the same as the typical monitored county in Colorado (median 47.5 across 30 counties), and higher than the typical monitored U.S. county (41). The main pollutant was ozone on 351 days. Across the years with fuller monitoring, the share of Good days rose: an average of 52% in 2010–2012 versus 69% in 2022–2024.

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%2010: Good 241 of 351 days2010: Moderate 108 of 351 days2010: Unhealthy for Sensitive Groups 2 of 351 days20102011: Good 144 of 365 days2011: Moderate 217 of 365 days2011: Unhealthy for Sensitive Groups 2 of 365 days2011: Unhealthy 2 of 365 days2012: Good 175 of 366 days2012: Moderate 188 of 366 days2012: Unhealthy for Sensitive Groups 3 of 366 days20122013: Good 187 of 365 days2013: Moderate 164 of 365 days2013: Unhealthy for Sensitive Groups 8 of 365 days2013: Unhealthy 5 of 365 days2013: Very Unhealthy 1 of 365 days2014: Good 264 of 365 days2014: Moderate 101 of 365 days20142015: Good 249 of 365 days2015: Moderate 116 of 365 days2016: Good 271 of 366 days2016: Moderate 95 of 366 days20162017: Good 237 of 365 days2017: Moderate 128 of 365 days2018: Good 215 of 365 days2018: Moderate 148 of 365 days2018: Unhealthy for Sensitive Groups 2 of 365 days20182019: Good 252 of 365 days2019: Moderate 113 of 365 days2020: Good 263 of 365 days2020: Moderate 99 of 365 days2020: Unhealthy for Sensitive Groups 3 of 365 days20202021: Good 212 of 365 days2021: Moderate 148 of 365 days2021: Unhealthy for Sensitive Groups 4 of 365 days2021: Unhealthy 1 of 365 days2022: Good 243 of 365 days2022: Moderate 120 of 365 days2022: Unhealthy for Sensitive Groups 2 of 365 days20222023: Good 247 of 365 days2023: Moderate 113 of 365 days2023: Unhealthy for Sensitive Groups 4 of 365 days2023: Unhealthy 1 of 365 days2024: Good 266 of 366 days2024: Moderate 96 of 366 days2024: Unhealthy for Sensitive Groups 4 of 366 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 year0501002010: 90th percentile AQI 612011: 90th percentile AQI 682012: 90th percentile AQI 742013: 90th percentile AQI 772014: 90th percentile AQI 552015: 90th percentile AQI 582016: 90th percentile AQI 552017: 90th percentile AQI 612018: 90th percentile AQI 712019: 90th percentile AQI 552020: 90th percentile AQI 572021: 90th percentile AQI 772022: 90th percentile AQI 642023: 90th percentile AQI 672024: 90th percentile AQI 672010: Median AQI 472011: Median AQI 532012: Median AQI 512013: Median AQI 502014: Median AQI 452015: Median AQI 462016: Median AQI 442017: Median AQI 462018: Median AQI 472019: Median AQI 472020: Median AQI 452021: Median AQI 482022: Median AQI 472023: Median AQI 472024: Median AQI 4620102012201420162018202020222024
  • 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
Ozone35196%
Fine particles (PM2.5)144%
Nitrogen dioxide (NO₂)1<1%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20243662669640004667142Ozone
202336524711341004767166Ozone
202236524312020004764122Ozone
202136521214841004877156Ozone
20203652639930004557115Ozone
201936525211300004755100Ozone
201836521514820004771108Ozone
20173652371280000466197Ozone
2016366271950000445590Ozone
201536524911600004658100Ozone
20143652641010000455587Ozone
201336518716485105077201Ozone
201236617518830005174103PM2.5
201136514421722005368156Ozone
201035124110820004761108Ozone

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 Colorado with a similar median AQI in 2024

All monitored counties in Colorado

Source: U.S. EPA AirData, “Annual AQI by County” files for 2010–2024 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem