EnviroNearby

Carbon County, Utah air quality history

Daily Air Quality Index summaries from EPA monitors in Carbon, Utah, 2011–2025.

72%
Good days in 2025
44
Median daily AQI, 2025
2
Days above 100 in 2025
364
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Carbon, Utah on 364 days. 263 of those days (72%) were in the Good range, and the median daily AQI was 44. That median is about the same as the typical monitored county in Utah (median 45 across 15 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 346 days. Across the years with fuller monitoring, the share of Good days rose: an average of 64% in 2011–2013 versus 80% in 2023–2025.

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%2011: Good 158 of 272 days2011: Moderate 113 of 272 days2011: Unhealthy for Sensitive Groups 1 of 272 days20112012: Good 231 of 365 days2012: Moderate 126 of 365 days2012: Unhealthy for Sensitive Groups 8 of 365 days2013: Good 252 of 362 days2013: Moderate 108 of 362 days2013: Unhealthy for Sensitive Groups 2 of 362 days20132014: Good 281 of 365 days2014: Moderate 84 of 365 days2015: Good 200 of 293 days2015: Moderate 91 of 293 days2015: Unhealthy for Sensitive Groups 2 of 293 days20152016: Good 230 of 312 days2016: Moderate 82 of 312 days2017: Good 262 of 364 days2017: Moderate 102 of 364 days20172018: Good 231 of 364 days2018: Moderate 128 of 364 days2018: Unhealthy for Sensitive Groups 5 of 364 days2019: Good 265 of 365 days2019: Moderate 99 of 365 days2019: Unhealthy for Sensitive Groups 1 of 365 days20192020: Good 308 of 350 days2020: Moderate 42 of 350 days2021: Good 265 of 365 days2021: Moderate 88 of 365 days2021: Unhealthy for Sensitive Groups 10 of 365 days2021: Unhealthy 2 of 365 days20212022: Good 321 of 364 days2022: Moderate 43 of 364 days2023: Good 329 of 363 days2023: Moderate 34 of 363 days20232024: Good 278 of 366 days2024: Moderate 87 of 366 days2024: Unhealthy for Sensitive Groups 1 of 366 days2025: Good 263 of 364 days2025: Moderate 99 of 364 days2025: Unhealthy for Sensitive Groups 2 of 364 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 year0501002011: 90th percentile AQI 772012: 90th percentile AQI 842013: 90th percentile AQI 672014: 90th percentile AQI 612015: 90th percentile AQI 642016: 90th percentile AQI 672017: 90th percentile AQI 672018: 90th percentile AQI 772019: 90th percentile AQI 642020: 90th percentile AQI 512021: 90th percentile AQI 742022: 90th percentile AQI 522023: 90th percentile AQI 502024: 90th percentile AQI 642025: 90th percentile AQI 672011: Median AQI 492012: Median AQI 452013: Median AQI 442014: Median AQI 442015: Median AQI 462016: Median AQI 442017: Median AQI 452018: Median AQI 462019: Median AQI 462020: Median AQI 432021: Median AQI 442022: Median AQI 432023: Median AQI 422024: Median AQI 442025: Median AQI 4420112013201520172019202120232025
  • 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
Ozone34695%
Fine particles (PM2.5)185%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253642639920004467108Ozone
20243662788710004464112Ozone
2023363329340000425070Ozone
2022364321430000435274Ozone
202136526588102004474155Ozone
2020350308420000435193Ozone
20193652659910004664108Ozone
201836423112850004677115Ozone
20173642621020000456790Ozone
2016312230820000446793Ozone
20152932009120004664112Ozone
2014365281840000446187Ozone
201336225210820004467115Ozone
201236523112680004584119Ozone
201127215811310004977108Ozone

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 Utah with a similar median AQI in 2025

All monitored counties in Utah

Source: U.S. EPA AirData, “Annual AQI by County” files for 2011–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem