Median AQI
19
Good
Montana · County air quality · 2025
Ravalli County, Montana
Median AQI 19 (Good). 81.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 19
- Median AQI
- 81.6%
- Good-air days
- 0
- Unhealthy days
- 57%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Ravalli County's air is good on balance, cleaner than the median US county, a median AQI of 19 with 81.6% of 174 monitored days in the Good band, driven mainly by PM2.5.
- 19
- median AQI · Good
- 81.6%
- days rated Good
- PM2.5
- main pollutant
- 57%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 80.
Data updated July 2026
- Good · 142 d · 81.6%
- Moderate · 32 d · 18.4%
How did Ravalli County's air break down in 2025?
Across 174 monitored days, 142 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 80 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 174 days monitored. Median AQI: 19 (Good).
Insights: Ravalli County, Montana. EPA monitors recorded a median Air Quality Index of 19 across 174 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 142 (82%) fell in the Good band (AQI 0–50), 32 (18%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 56, while the worst single-day peak hit 80 (Moderate). Residents averaged about 24.5 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (174 days). Across the 2020–2025 trend window, good days shifted by -159 and the median AQI moved +4 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 80, moderate but never Unhealthy. Nearby counties show comparable readings: Beaverhead (100.0% good, AQI 12); Custer (91.2% good, AQI 39); Dawson (95.0% good, AQI 14); Fergus (92.2% good, AQI 44); Flathead (82.1% good, AQI 40); Gallatin (99.1% good, AQI 14).
Air Quality Summary
Good Days
81.6%
142 of 174 monitored days
6.6pp vs 75% target
Max AQI Recorded
80
Moderate
Health Grade
Good
90th-pct AQI 56
Ravalli County, Good days share 81.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
Ravalli 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 174 monitored days across EPA AQI categories.
Good
142
82%
Moderate
32
18%
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 Ravalli County.
- PM2.5 · 174 days · 100.0%
Health Impact Assessment
Good
Ravalli County's air quality is rated Good based on 81.6% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 81.6% of monitored days in 2025, with a median AQI of 19. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 174 of 174 monitored days.
5-Year Air Quality Trend
Air quality is stable in Ravalli County. Best year: 2020 (301 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 301 | 52 | 3 | 5 | 15 | 185 |
| 2021 | 268 | 67 | 18 | 5 | 28 | 159 |
| 2022 | 287 | 64 | 2 | 8 | 27 | 263 |
| 2023 | 293 | 69 | 1 | 0 | 22 | 110 |
| 2024 | 254 | 92 | 10 | 6 | 24 | 182 |
| 2025 | 142 | 32 | 0 | 0 | 19 | 80 |
How does Ravalli County compare?
How Ravalli County compares
Good-day share better than US avg
Ravalli County 81.6%
Beaverhead County, Montana 100.0%
US average 76.5%
Median AQI better than US avg
Ravalli County 19
Beaverhead County, Montana 12
US average 38
Unhealthy days / yr about average
Ravalli County 0
Beaverhead County, Montana 0
US average 0
Other Counties in Montana
Air quality comparison for nearby counties in Montana.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Ravalli County.
Adams County, Washington
AQI 19 · 94.7% good
Bonneville County, Idaho
AQI 19 · 94.9% good
Elko County, Nevada
AQI 19 · 90.8% good
Grays Harbor County, Washington
AQI 19 · 97.9% good
Jefferson County, Washington
AQI 19 · 96.5% good
Luna County, New Mexico
AQI 19 · 79.5% good
What Ravalli 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 19 means for exposure. Health guidance
- See how Ravalli County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Ravalli County with its Montana neighbours before drawing a conclusion about the region. All of Montana
Based on 174 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 Ravalli County, Montana? ▼
Ravalli County has a median Air Quality Index (AQI) of 19, rated "Good." 81.6% of monitored days (142 out of 174) had good air quality in 2025.
What is the main pollutant in Ravalli County? ▼
The primary pollutant in Ravalli County is Fine Particles (PM2.5), which was the main AQI driver on 174 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Ravalli County have? ▼
In 2025, Ravalli County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 80.
Is the air quality in Ravalli County getting better or worse? ▼
Air quality in Ravalli County is stable based on 5-year trends (2020-2025). Best year: 2020 with 301 good days. Worst year: 2025 with 142 good days.
What does AQI 19 mean for health? ▼
Ravalli County's median AQI of 19 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 Ravalli County compare to other counties in Montana? ▼
Ravalli County has 81.6% good air days. Nearby counties in Montana: Beaverhead (100.0% good), Custer (91.2% good), Dawson (95.0% good), Fergus (92.2% good), Flathead (82.1% good), Gallatin (99.1% good).
What is the 90th percentile AQI in Ravalli County? ▼
The 90th percentile AQI for Ravalli County is 56, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 80 (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.