Median AQI
7
Good
Wyoming · County air quality · 2025
Carbon County, Wyoming
Median AQI 7 (Good). 100.0% of monitored days rated Good, direct from EPA Air Quality System stations.
- 7
- Median AQI
- 100.0%
- Good-air days
- 0
- Unhealthy days
- 96%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Carbon County's air is good on balance, among the cleanest 5% of US counties, a median AQI of 7 with 100.0% of 181 monitored days in the Good band, driven mainly by NO2.
- 7
- median AQI · Good
- 100.0%
- days rated Good
- NO2
- main pollutant
- 96%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 30.
Data updated July 2026
- Good · 181 d · 100.0%
How did Carbon County's air break down in 2025?
Across 181 monitored days, 181 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 30 (Good).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 7 (Good).
Insights: Carbon County, Wyoming. EPA monitors recorded a median Air Quality Index of 7 across 181 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 181 (100%) fell in the Good band (AQI 0–50), 0 (0%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 18, while the worst single-day peak hit 30 (Good). Residents averaged about 30.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as NO2 (181 days). Across the 2020–2025 trend window, good days shifted by -123 and the median AQI moved -1 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 30, good but never Unhealthy. Nearby counties show comparable readings: Albany (51.9% good, AQI 50); Campbell (77.3% good, AQI 43); Converse (94.5% good, AQI 41); Fremont (61.3% good, AQI 48); Johnson (90.6% good, AQI 42); Laramie (69.8% good, AQI 47).
Air Quality Summary
Good Days
100.0%
181 of 181 monitored days
25.0pp vs 75% target
Max AQI Recorded
30
Good
Health Grade
Excellent
90th-pct AQI 18
Carbon County, Good days share 100.0%
National avg
Share of monitored days at AQI 0-50 (Good band).
Carbon County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 181 monitored days across EPA AQI categories.
Good
181
100%
Moderate
0
0%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Carbon County.
- NO₂ · 181 days · 100.0%
Health Impact Assessment
Excellent
Carbon County's air quality is rated Excellent based on 100.0% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 100.0% of monitored days in 2025, with a median AQI of 7. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is NO2, driving AQI on 181 of 181 monitored days.
5-Year Air Quality Trend
Air quality is stable in Carbon County. Best year: 2023 (362 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 304 | 0 | 0 | 0 | 8 | 31 |
| 2021 | 348 | 0 | 0 | 0 | 10 | 37 |
| 2022 | 361 | 0 | 0 | 0 | 9 | 27 |
| 2023 | 362 | 0 | 0 | 0 | 8 | 33 |
| 2024 | 356 | 0 | 0 | 0 | 8 | 35 |
| 2025 | 181 | 0 | 0 | 0 | 7 | 30 |
How does Carbon County compare?
How Carbon County compares
Good-day share better than US avg
Carbon County 100.0%
Albany County, Wyoming 51.9%
US average 76.5%
Median AQI better than US avg
Carbon County 7
Albany County, Wyoming 50
US average 38
Unhealthy days / yr about average
Carbon County 0
Albany County, Wyoming 0
US average 0
Other Counties in Wyoming
Air quality comparison for nearby counties in Wyoming.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Carbon County.
Keweenaw County, Michigan
AQI 7 · 100.0% good
Matanuska-Susitna County, Alaska
AQI 7 · 90.3% good
North Slope County, Alaska
AQI 7 · 100.0% good
Wilson County, Texas
AQI 7 · 100.0% good
Catron County, New Mexico
AQI 8 · 100.0% good
Hopewell City County, Virginia
AQI 6 · 100.0% good
What Carbon County's air means for you
The air here stays in the breathable range year-round, with NO2 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-NO2 days, the guide explains what a median of 7 means for exposure. Health guidance
- See how Carbon County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Carbon County with its Wyoming neighbours before drawing a conclusion about the region. All of Wyoming
Based on 181 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Carbon County, Wyoming? ▼
Carbon County has a median Air Quality Index (AQI) of 7, rated "Good." 100.0% of monitored days (181 out of 181) had good air quality in 2025.
What is the main pollutant in Carbon County? ▼
The primary pollutant in Carbon County is Nitrogen Dioxide (NO2), which was the main AQI driver on 181 days (100% of monitored days). Irritates airways. Long-term exposure linked to respiratory infections.
How many unhealthy air days does Carbon County have? ▼
In 2025, Carbon County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 30.
Is the air quality in Carbon County getting better or worse? ▼
Air quality in Carbon County is stable based on 5-year trends (2020-2025). Best year: 2023 with 362 good days. Worst year: 2025 with 181 good days.
What does AQI 7 mean for health? ▼
Carbon County's median AQI of 7 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Carbon County compare to other counties in Wyoming? ▼
Carbon County has 100.0% good air days. Nearby counties in Wyoming: Albany (51.9% good), Campbell (77.3% good), Converse (94.5% good), Fremont (61.3% good), Johnson (90.6% good), Laramie (69.8% good).
What is the 90th percentile AQI in Carbon County? ▼
The 90th percentile AQI for Carbon County is 18, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 30 (Good).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.