Metro area air quality · 2025
Missoula, MT
Median AQI 38 (Good). 81.6% of monitored days rated Good across this metro's EPA monitoring network.
- 38
- Median AQI
- 81.6%
- Good-air days
- 0
- Unhealthy days
- 71%
- Cleaner than US metros
Missoula, MT posted a 2025 median AQI of 38 (Good) with 81.6% Good days
According to the U.S. EPA Air Quality System, the Missoula, MT CBSA recorded a median AQI of 38 across 365 monitored days in 2025, with 81.6% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The Missoula, MT CBSA's 81.6% Good-day share places it cleaner than 71% of US metros in 2025.
- Closest median-AQI peer
- Appleton, WI (72.3% Good, median AQI 38) is the closest nationwide median-AQI peer to Missoula, MT.
- 2020–2025 Good-day shift
- Missoula, MT's Good-day share moved +37.7 points from 2020 to 2025 (median AQI -16).
- Median AQI
- Median AQI: 38
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Missoula, MT sits in the upper Good-day tercile among EPA CBSA metros on this site (81.6% of 365 monitored days). On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 38 and 81.6% of 365 monitored days in the Good band.
- 38
- median AQI · Good
- 81.6%
- days rated Good
- 71%
- cleaner than US metros
- 98
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Missoula, MT metro's Good-day share rose from 65.3% to 81.6% between the 2024 and 2025 EPA annual releases, a change of +16.4 percentage points.
- Missoula, MT metro's peak single-day AQI fell from 153 to 98 between the 2024 and 2025 EPA annual releases, a change of -55 points.
- Missoula, MT metro's median AQI fell from 43 to 38 between the 2024 and 2025 EPA annual releases, a change of -5 points.
- Missoula, MT metro's Unhealthy-category days fell from 1 to 0 between the 2024 and 2025 EPA annual releases, a change of -1 days.
Missoula, MT sits in the upper Good-day tercile among EPA CBSA metros on this site (81.6% of 365 monitored days). Signature read: 81.6% Good-day share (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 38 over 365 measured days in 2025 (Good / Good). The monitored-day split lands at 298 Good (82%), 67 Moderate (18%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 56; the highest single-day reading hit 98 (Moderate).
Across 2020–2025, Good-day share shifted +37.7 points and median AQI moved -16 (improving). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Appleton, WI (72.3% good, AQI 38); Billings, MT (86.3% good, AQI 38); Burlington-South Burlington, VT (87.7% good, AQI 38).
Air Quality Summary
Median AQI
38
Good
Good Days
81.6%
298 of 365 days
Max AQI
98
Moderate
Health Grade
Good
90th pct: 56
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
298
82%
Moderate
67
18%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Missoula, MT metro area's air quality is rated Good based on 81.6% good air days. No unhealthy air days were recorded in 2025.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the Missoula, MT metro compare?
How Missoula, MT compares
5-Year Air Quality Trend
Air quality is improving in the Missoula, MT metro. Highest Good-day share: 2025 (81.6%, 298 of 365 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 155 | 192 | 6 | 54 | 185 |
| 2021 | 122 | 213 | 6 | 56 | 162 |
| 2022 | 149 | 201 | 4 | 54 | 190 |
| 2023 | 156 | 200 | 0 | 53 | 134 |
| 2024 | 237 | 125 | 1 | 43 | 153 |
| 2025 | 298 | 67 | 0 | 38 | 98 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Missoula, MT (38).
Appleton, WI
Median AQI 38 · 72.3% Good-day share
Billings, MT
Median AQI 38 · 86.3% Good-day share
Burlington-South Burlington, VT
Median AQI 38 · 87.7% Good-day share
Charlottesville, VA
Median AQI 38 · 81.0% Good-day share
Corning, NY
Median AQI 38 · 83.3% Good-day share
Dickinson, ND
Median AQI 38 · 82.7% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Missoula, MT's 0 (independent of median AQI).
Aberdeen, SD
0 unhealthy-or-worse days · median AQI 27
Aberdeen, WA
0 unhealthy-or-worse days · median AQI 22
Adrian, MI
0 unhealthy-or-worse days · median AQI 41
Akron, OH
0 unhealthy-or-worse days · median AQI 45
Albany, GA
0 unhealthy-or-worse days · median AQI 46
Albany, OR
0 unhealthy-or-worse days · median AQI 27
Frequently Asked Questions
How many unhealthy air days does Missoula, MT have? ▼
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Is air quality in Missoula, MT getting better or worse? ▼
What does AQI 38 mean for health? ▼
How does Missoula, MT compare to other metro areas? ▼
What is the 90th percentile AQI for Missoula, MT? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Missoula, MT, 2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Missoula, MT · 2020–2025