EnviroNearby

Campbell County, Wyoming air quality history

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

74%
Good days in 2025
44
Median daily AQI, 2025
2
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 Campbell, Wyoming on 365 days. 271 of those days (74%) were in the Good range, and the median daily AQI was 44. That median is higher than the typical monitored county in Wyoming (median 41 across 17 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 245 days. Across the years with fuller monitoring, the share of Good days rose: an average of 59% in 2000–2002 versus 68% in 2023–2025.

Years with fewer than 120 monitored days (1994, 1995, 1996, 1997, 1998, 1999…) 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 5 of 5 days19851986: Good 53 of 53 days1987: Good 26 of 26 days1991: Good 51 of 60 days1991: Moderate 9 of 60 days1992: Good 54 of 61 days1992: Moderate 7 of 61 days1993: Good 54 of 61 days1993: Moderate 7 of 61 days19931994: Good 57 of 62 days1994: Moderate 5 of 62 days1995: Good 55 of 62 days1995: Moderate 7 of 62 days1996: Good 51 of 61 days1996: Moderate 10 of 61 days1997: Good 57 of 63 days1997: Moderate 6 of 63 days1998: Good 52 of 61 days1998: Moderate 9 of 61 days19981999: Good 54 of 88 days1999: Moderate 34 of 88 days2000: Good 109 of 163 days2000: Moderate 51 of 163 days2000: Unhealthy for Sensitive Groups 2 of 163 days2000: Unhealthy 1 of 163 days2001: Good 210 of 365 days2001: Moderate 147 of 365 days2001: Unhealthy for Sensitive Groups 5 of 365 days2001: Unhealthy 3 of 365 days2002: Good 192 of 365 days2002: Moderate 160 of 365 days2002: Unhealthy for Sensitive Groups 11 of 365 days2002: Unhealthy 2 of 365 days2003: Good 184 of 365 days2003: Moderate 168 of 365 days2003: Unhealthy for Sensitive Groups 13 of 365 days20032004: Good 212 of 366 days2004: Moderate 149 of 366 days2004: Unhealthy for Sensitive Groups 3 of 366 days2004: Hazardous 2 of 366 days2005: Good 210 of 365 days2005: Moderate 143 of 365 days2005: Unhealthy for Sensitive Groups 12 of 365 days2006: Good 184 of 365 days2006: Moderate 175 of 365 days2006: Unhealthy for Sensitive Groups 6 of 365 days2007: Good 187 of 365 days2007: Moderate 164 of 365 days2007: Unhealthy for Sensitive Groups 12 of 365 days2007: Unhealthy 2 of 365 days2008: Good 178 of 366 days2008: Moderate 186 of 366 days2008: Unhealthy for Sensitive Groups 2 of 366 days20082009: Good 239 of 365 days2009: Moderate 125 of 365 days2009: Unhealthy for Sensitive Groups 1 of 365 days2010: Good 227 of 365 days2010: Moderate 137 of 365 days2010: Unhealthy for Sensitive Groups 1 of 365 days2011: Good 197 of 365 days2011: Moderate 163 of 365 days2011: Unhealthy for Sensitive Groups 4 of 365 days2011: Unhealthy 1 of 365 days2012: Good 128 of 366 days2012: Moderate 223 of 366 days2012: Unhealthy for Sensitive Groups 13 of 366 days2012: Unhealthy 2 of 366 days2013: Good 205 of 365 days2013: Moderate 159 of 365 days2013: Unhealthy for Sensitive Groups 1 of 365 days20132014: Good 253 of 365 days2014: Moderate 111 of 365 days2014: Unhealthy for Sensitive Groups 1 of 365 days2015: Good 241 of 365 days2015: Moderate 121 of 365 days2015: Unhealthy for Sensitive Groups 2 of 365 days2015: Unhealthy 1 of 365 days2016: Good 252 of 366 days2016: Moderate 113 of 366 days2016: Unhealthy for Sensitive Groups 1 of 366 days2017: Good 229 of 365 days2017: Moderate 129 of 365 days2017: Unhealthy for Sensitive Groups 4 of 365 days2017: Unhealthy 3 of 365 days2018: Good 256 of 365 days2018: Moderate 105 of 365 days2018: Unhealthy for Sensitive Groups 2 of 365 days2018: Unhealthy 2 of 365 days20182019: Good 301 of 365 days2019: Moderate 63 of 365 days2019: Unhealthy for Sensitive Groups 1 of 365 days2020: Good 247 of 366 days2020: Moderate 116 of 366 days2020: Unhealthy for Sensitive Groups 3 of 366 days2021: Good 218 of 365 days2021: Moderate 131 of 365 days2021: Unhealthy for Sensitive Groups 16 of 365 days2022: Good 210 of 365 days2022: Moderate 146 of 365 days2022: Unhealthy for Sensitive Groups 7 of 365 days2022: Unhealthy 1 of 365 days2022: Hazardous 1 of 365 days2023: Good 245 of 365 days2023: Moderate 113 of 365 days2023: Unhealthy for Sensitive Groups 6 of 365 days2023: Unhealthy 1 of 365 days20232024: Good 232 of 366 days2024: Moderate 129 of 366 days2024: Unhealthy for Sensitive Groups 3 of 366 days2024: Unhealthy 2 of 366 days2025: Good 271 of 365 days2025: Moderate 92 of 365 days2025: Unhealthy for Sensitive Groups 1 of 365 days2025: Unhealthy 1 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 year0501001985: 90th percentile AQI 191986: 90th percentile AQI 271987: 90th percentile AQI 381991: 90th percentile AQI 531992: 90th percentile AQI 511993: 90th percentile AQI 511994: 90th percentile AQI 461995: 90th percentile AQI 521996: 90th percentile AQI 561997: 90th percentile AQI 501998: 90th percentile AQI 521999: 90th percentile AQI 762000: 90th percentile AQI 722001: 90th percentile AQI 772002: 90th percentile AQI 802003: 90th percentile AQI 822004: 90th percentile AQI 672005: 90th percentile AQI 742006: 90th percentile AQI 782007: 90th percentile AQI 842008: 90th percentile AQI 752009: 90th percentile AQI 642010: 90th percentile AQI 692011: 90th percentile AQI 732012: 90th percentile AQI 902013: 90th percentile AQI 642014: 90th percentile AQI 592015: 90th percentile AQI 662016: 90th percentile AQI 622017: 90th percentile AQI 692018: 90th percentile AQI 642019: 90th percentile AQI 562020: 90th percentile AQI 682021: 90th percentile AQI 872022: 90th percentile AQI 742023: 90th percentile AQI 672024: 90th percentile AQI 742025: 90th percentile AQI 621985: Median AQI 141986: Median AQI 161987: Median AQI 261991: Median AQI 231992: Median AQI 241993: Median AQI 241994: Median AQI 261995: Median AQI 231996: Median AQI 241997: Median AQI 251998: Median AQI 311999: Median AQI 442000: Median AQI 322001: Median AQI 482002: Median AQI 492003: Median AQI 502004: Median AQI 472005: Median AQI 472006: Median AQI 502007: Median AQI 502008: Median AQI 512009: Median AQI 442010: Median AQI 462011: Median AQI 492012: Median AQI 572013: Median AQI 482014: Median AQI 442015: Median AQI 462016: Median AQI 442017: Median AQI 452018: Median AQI 432019: Median AQI 412020: Median AQI 442021: Median AQI 442022: Median AQI 482023: Median AQI 452024: Median AQI 442025: Median AQI 44198519931998200320082013201820232025
  • 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
Ozone24567%
Coarse particles (PM10)10729%
Fine particles (PM2.5)134%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253652719211004462156Ozone
202436623212932004474161Ozone
202336524511361004567177Ozone
202236521014671014874584PM10
2021365218131160004487143Ozone
202036624711630004468124Ozone
20193653016310004156111Ozone
201836525610522004364169Ozone
201736522912943004569169Ozone
201636625211310004462141Ozone
201536524112121004666198Ozone
201436525311110004459109Ozone
201336520515910004864106Ozone
2012366128223132005790156PM10
201136519716341004973169Ozone
201036522713710004669124Ozone
200936523912510004464101Ozone
200836617818620005175140Ozone
2007365187164122005084158Ozone
200636518417560005078133Ozone
2005365210143120004774131Ozone
200436621214930024767523Ozone
2003365184168130005082150Ozone
2002365192160112004980168Ozone
200136521014753004877167PM10
20001631095121003272170PM10
19998854340000447697PM10
1998615290000315259PM10
1997635760000255083PM10
19966151100000245675PM10
1995625570000235279PM10
1994625750000264670PM10
1993615470000245154PM10
1992615470000245179PM10
1991605190000235367PM10
1987262600000263839PM10
1986535300000162733PM10
19855500000141919PM10

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