EnviroNearby

Cache County, Utah air quality history

Daily Air Quality Index summaries from EPA monitors in Cache, Utah, 1982–2025.

66%
Good days in 2025
44
Median daily AQI, 2025
0
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Cache, Utah on 365 days. 241 of those days (66%) 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 269 days. Across the years with fuller monitoring, the share of Good days fell: an average of 89% in 1982–1995 versus 64% 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%1982: Good 208 of 243 days1982: Moderate 35 of 243 days19821983: Good 111 of 122 days1983: Moderate 11 of 122 days1995: Good 180 of 201 days1995: Moderate 21 of 201 days1996: Good 237 of 325 days1996: Moderate 86 of 325 days1996: Unhealthy for Sensitive Groups 2 of 325 days1997: Good 277 of 312 days1997: Moderate 35 of 312 days1998: Good 258 of 322 days1998: Moderate 60 of 322 days1998: Unhealthy for Sensitive Groups 4 of 322 days19981999: Good 247 of 303 days1999: Moderate 56 of 303 days2000: Good 222 of 324 days2000: Moderate 90 of 324 days2000: Unhealthy for Sensitive Groups 11 of 324 days2000: Unhealthy 1 of 324 days2001: Good 209 of 324 days2001: Moderate 99 of 324 days2001: Unhealthy for Sensitive Groups 10 of 324 days2001: Unhealthy 6 of 324 days2002: Good 190 of 345 days2002: Moderate 140 of 345 days2002: Unhealthy for Sensitive Groups 8 of 345 days2002: Unhealthy 6 of 345 days2002: Very Unhealthy 1 of 345 days2003: Good 202 of 364 days2003: Moderate 152 of 364 days2003: Unhealthy for Sensitive Groups 10 of 364 days20032004: Good 216 of 366 days2004: Moderate 111 of 366 days2004: Unhealthy for Sensitive Groups 20 of 366 days2004: Unhealthy 17 of 366 days2004: Very Unhealthy 2 of 366 days2005: Good 200 of 365 days2005: Moderate 127 of 365 days2005: Unhealthy for Sensitive Groups 25 of 365 days2005: Unhealthy 13 of 365 days2006: Good 144 of 365 days2006: Moderate 212 of 365 days2006: Unhealthy for Sensitive Groups 8 of 365 days2006: Unhealthy 1 of 365 days2007: Good 139 of 365 days2007: Moderate 208 of 365 days2007: Unhealthy for Sensitive Groups 18 of 365 days2008: Good 100 of 366 days2008: Moderate 251 of 366 days2008: Unhealthy for Sensitive Groups 11 of 366 days2008: Unhealthy 4 of 366 days20082009: Good 100 of 365 days2009: Moderate 237 of 365 days2009: Unhealthy for Sensitive Groups 24 of 365 days2009: Unhealthy 4 of 365 days2010: Good 119 of 365 days2010: Moderate 226 of 365 days2010: Unhealthy for Sensitive Groups 14 of 365 days2010: Unhealthy 6 of 365 days2011: Good 157 of 365 days2011: Moderate 198 of 365 days2011: Unhealthy for Sensitive Groups 5 of 365 days2011: Unhealthy 5 of 365 days2012: Good 173 of 366 days2012: Moderate 186 of 366 days2012: Unhealthy for Sensitive Groups 7 of 366 days2013: Good 137 of 365 days2013: Moderate 184 of 365 days2013: Unhealthy for Sensitive Groups 28 of 365 days2013: Unhealthy 16 of 365 days20132014: Good 251 of 365 days2014: Moderate 101 of 365 days2014: Unhealthy for Sensitive Groups 13 of 365 days2015: Good 251 of 365 days2015: Moderate 110 of 365 days2015: Unhealthy for Sensitive Groups 3 of 365 days2015: Unhealthy 1 of 365 days2016: Good 241 of 366 days2016: Moderate 117 of 366 days2016: Unhealthy for Sensitive Groups 8 of 366 days2017: Good 220 of 365 days2017: Moderate 128 of 365 days2017: Unhealthy for Sensitive Groups 13 of 365 days2017: Unhealthy 4 of 365 days2018: Good 205 of 365 days2018: Moderate 153 of 365 days2018: Unhealthy for Sensitive Groups 7 of 365 days20182019: Good 247 of 365 days2019: Moderate 104 of 365 days2019: Unhealthy for Sensitive Groups 14 of 365 days2020: Good 205 of 366 days2020: Moderate 152 of 366 days2020: Unhealthy for Sensitive Groups 5 of 366 days2020: Unhealthy 4 of 366 days2021: Good 213 of 365 days2021: Moderate 142 of 365 days2021: Unhealthy for Sensitive Groups 10 of 365 days2022: Good 223 of 365 days2022: Moderate 135 of 365 days2022: Unhealthy for Sensitive Groups 6 of 365 days2022: Unhealthy 1 of 365 days2023: Good 219 of 365 days2023: Moderate 138 of 365 days2023: Unhealthy for Sensitive Groups 4 of 365 days2023: Unhealthy 4 of 365 days20232024: Good 238 of 366 days2024: Moderate 127 of 366 days2024: Unhealthy for Sensitive Groups 1 of 366 days2025: Good 241 of 365 days2025: Moderate 124 of 365 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 year0501001501982: 90th percentile AQI 581983: 90th percentile AQI 491995: 90th percentile AQI 511996: 90th percentile AQI 711997: 90th percentile AQI 511998: 90th percentile AQI 671999: 90th percentile AQI 612000: 90th percentile AQI 782001: 90th percentile AQI 802002: 90th percentile AQI 842003: 90th percentile AQI 842004: 90th percentile AQI 1042005: 90th percentile AQI 1042006: 90th percentile AQI 772007: 90th percentile AQI 902008: 90th percentile AQI 842009: 90th percentile AQI 882010: 90th percentile AQI 872011: 90th percentile AQI 742012: 90th percentile AQI 742013: 90th percentile AQI 1142014: 90th percentile AQI 612015: 90th percentile AQI 692016: 90th percentile AQI 682017: 90th percentile AQI 742018: 90th percentile AQI 772019: 90th percentile AQI 692020: 90th percentile AQI 722021: 90th percentile AQI 822022: 90th percentile AQI 712023: 90th percentile AQI 712024: 90th percentile AQI 712025: 90th percentile AQI 641982: Median AQI 371983: Median AQI 351995: Median AQI 381996: Median AQI 361997: Median AQI 351998: Median AQI 391999: Median AQI 402000: Median AQI 382001: Median AQI 452002: Median AQI 482003: Median AQI 482004: Median AQI 472005: Median AQI 492006: Median AQI 542007: Median AQI 572008: Median AQI 562009: Median AQI 552010: Median AQI 552011: Median AQI 522012: Median AQI 512013: Median AQI 542014: Median AQI 452015: Median AQI 432016: Median AQI 462017: Median AQI 472018: Median AQI 482019: Median AQI 462020: Median AQI 482021: Median AQI 452022: Median AQI 462023: Median AQI 482024: Median AQI 442025: Median AQI 4419821998200320082013201820232025
  • 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
Ozone26974%
Fine particles (PM2.5)9626%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253652411240000446487Ozone
202436623812710004471101Ozone
202336521913844004871187Ozone
202236522313561004671155Ozone
2021365213142100004582129Ozone
202036620515254004872162PM2.5
2019365247104140004669147Ozone
201836520515370004877133Ozone
2017365220128134004774172Ozone
201636624111780004668129Ozone
201536525111031004369159PM2.5
2014365251101130004561141Ozone
201336513718428160054114182PM2.5
201236617318670005174116PM2.5
201136515719855005274175PM2.5
2010365119226146005587164PM2.5
2009365100237244005588168PM2.5
2008366100251114005684165PM2.5
2007365139208180005790143PM2.5
200636514421281005477152PM2.5
200536520012725130049104173PM2.5
200436621611120172047104208PM2.5
2003364202152100004884126Ozone
200234519014086104884213PM2.5
200132420999106004580174Ozone
200032422290111003878157Ozone
19993032475600004061100Ozone
19983222586040003967119Ozone
1997312277350000355187Ozone
19963252378620003671105Ozone
1995201180210000385184Ozone
1983122111110000354989Ozone
1982243208350000375877Ozone

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 1982–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem