Median AQI
14
Good
Wyoming · County air quality · 2025
Park County, Wyoming
Median AQI 14 (Good). 99.5% of monitored days rated Good, direct from EPA Air Quality System stations.
- 14
- Median AQI
- 99.5%
- Good-air days
- 0
- Unhealthy days
- 95%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Park County's air is good on balance, among the cleanest 5% of US counties, a median AQI of 14 with 99.5% of 198 monitored days in the Good band, driven mainly by PM2.5.
- 14
- median AQI · Good
- 99.5%
- days rated Good
- PM2.5
- main pollutant
- 95%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 61.
Data updated July 2026
- Good · 197 d · 99.5%
- Moderate · 1 d · 0.5%
How did Park County's air break down in 2025?
Across 198 monitored days, 197 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 61 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 198 days monitored. Median AQI: 14 (Good).
Insights: Park County, Wyoming. EPA monitors recorded a median Air Quality Index of 14 across 198 measured days in 2025, earning a Good classification and a Excellent health grade. Of those days, 197 (99%) fell in the Good band (AQI 0–50), 1 (1%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 27, while the worst single-day peak hit 61 (Moderate). Residents averaged about 29.8 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (198 days). Across the 2020–2025 trend window, good days shifted by +85 and the median AQI moved -1 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 61, moderate but never Unhealthy. Nearby counties show comparable readings: Albany (51.9% good, AQI 50); Campbell (77.3% good, AQI 43); Carbon (100.0% good, AQI 7); Converse (94.5% good, AQI 41); Fremont (61.3% good, AQI 48); Johnson (90.6% good, AQI 42).
Air Quality Summary
Good Days
99.5%
197 of 198 monitored days
24.5pp vs 75% target
Max AQI Recorded
61
Moderate
Health Grade
Excellent
90th-pct AQI 27
Park County, Good days share 99.5%
National avg
Share of monitored days at AQI 0-50 (Good band).
Park 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 198 monitored days across EPA AQI categories.
Good
197
99%
Moderate
1
1%
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 Park County.
- PM2.5 · 198 days · 100.0%
Health Impact Assessment
Excellent
Park County's air quality is rated Excellent based on 99.5% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 99.5% of monitored days in 2025, with a median AQI of 14. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 198 of 198 monitored days.
5-Year Air Quality Trend
Air quality is improving in Park County. Best year: 2023 (343 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 112 | 8 | 2 | 0 | 15 | 113 |
| 2021 | 129 | 23 | 0 | 0 | 14 | 98 |
| 2022 | 314 | 30 | 0 | 0 | 20 | 83 |
| 2023 | 343 | 16 | 1 | 0 | 14 | 122 |
| 2024 | 322 | 33 | 0 | 0 | 13 | 88 |
| 2025 | 197 | 1 | 0 | 0 | 14 | 61 |
How does Park County compare?
How Park County compares
Good-day share better than US avg
Park County 99.5%
Albany County, Wyoming 51.9%
US average 76.5%
Median AQI better than US avg
Park County 14
Albany County, Wyoming 50
US average 38
Unhealthy days / yr about average
Park 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 Park County.
Apache County, Arizona
AQI 14 · 99.6% good
Dawson County, Montana
AQI 14 · 95.0% good
Gallatin County, Montana
AQI 14 · 99.1% good
Hughes County, South Dakota
AQI 14 · 94.4% good
Klickitat County, Washington
AQI 14 · 84.2% good
Platte County, Wyoming
AQI 14 · 87.7% good
What Park County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 14 means for exposure. Health guidance
- See how Park County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Park County with its Wyoming neighbours before drawing a conclusion about the region. All of Wyoming
Based on 198 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 Park County, Wyoming? ▼
Park County has a median Air Quality Index (AQI) of 14, rated "Good." 99.5% of monitored days (197 out of 198) had good air quality in 2025.
What is the main pollutant in Park County? ▼
The primary pollutant in Park County is Fine Particles (PM2.5), which was the main AQI driver on 198 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Park County have? ▼
In 2025, Park County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 61.
Is the air quality in Park County getting better or worse? ▼
Air quality in Park County is improving based on 5-year trends (2020-2025). Best year: 2023 with 343 good days. Worst year: 2020 with 112 good days.
What does AQI 14 mean for health? ▼
Park County's median AQI of 14 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 Park County compare to other counties in Wyoming? ▼
Park County has 99.5% good air days. Nearby counties in Wyoming: Albany (51.9% good), Campbell (77.3% good), Carbon (100.0% good), Converse (94.5% good), Fremont (61.3% good), Johnson (90.6% good).
What is the 90th percentile AQI in Park County? ▼
The 90th percentile AQI for Park County is 27, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 61 (Moderate).
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.