Metro area air quality · 2024
Great Falls, MT
Median AQI 46 (Good). 59.8% of monitored days rated Good across this metro's EPA monitoring network.
- 46
- Median AQI
- 59.8%
- Good-air days
- 0
- Unhealthy days
Great Falls, MT posted a 2024 median AQI of 46 (Good) with 59.8% Good days
According to the U.S. EPA Air Quality System, the Great Falls, MT CBSA recorded a median AQI of 46 across 87 monitored days in 2024, with 59.8% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Closest median-AQI peer
- Ada, OK (71.6% Good, median AQI 43) is the closest nationwide median-AQI peer to Great Falls, MT.
- 2020–2024 Good-day shift
- Great Falls, MT's Good-day share moved -28.4 points from 2020 to 2024 (median AQI +22).
- Median AQI
- Median AQI: 46
- Good days
- Good days: 59.8%
Aggregated from EPA Air Quality System (2024), 87 monitored days. EPA AQS →
The verdict
The Great Falls, MT metro runs good on the EPA scale, a median AQI of 46 with 59.8% of 87 monitored days in the Good band.
- 46
- median AQI · Good
- 59.8%
- days rated Good
- 74
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2024.
Annual release change
What changed in the 2023 EPA annual release
- Great Falls, MT metro's Good-day share fell from 90.5% to 50.9% between the 2022 and 2023 EPA annual releases, a change of -39.6 percentage points.
- Great Falls, MT metro's median AQI rose from 23 to 50 between the 2022 and 2023 EPA annual releases, a change of +27 points.
- Great Falls, MT metro's peak single-day AQI rose from 128 to 170 between the 2022 and 2023 EPA annual releases, a change of +42 points.
- Great Falls, MT metro's Unhealthy-category days rose from 0 to 1 between the 2022 and 2023 EPA annual releases, a change of +1 days.
Insights: Great Falls, MT metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 46 over 87 measured days in 2024, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 52 Good days (60%), 35 Moderate (40%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 58 while the highest single-day reading hit 74 (Moderate). Metro residents averaged roughly 17.9 clean-air days per 30-day window across the reporting year.
Across the 2020–2024 trend window, the share of monitored days rated Good shifted by -28.4 points (measured against 356 monitored days in 2020 and 87 in 2024, so raw day counts are not comparable) and the median AQI moved +22 points, which classifies the multi-year trajectory as worsening. The metro recorded no Unhealthy-tier days in this annual dataset. Metros with comparable AQI profiles include Ada, OK (71.6% good, AQI 43); Summerville, GA (96.3% good, AQI 39); Americus, GA (93.4% good, AQI 38).
Air Quality Summary
Median AQI
46
Good
Good Days
59.8%
52 of 87 days
Max AQI
74
Moderate
Health Grade
Moderate
90th pct: 58
AQI Day Breakdown (2024)
Distribution of 87 monitored days across EPA AQI categories.
Good
52
60%
Moderate
35
40%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Great Falls, MT metro area's air quality is rated Moderate based on 59.8% good air days. No unhealthy air days were recorded in 2024.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the Great Falls, MT metro compare?
How Great Falls, MT compares
5-Year Air Quality Trend
Air quality is worsening in the Great Falls, MT metro. Best year: 2022 (323 good days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 314 | 42 | 0 | 24 | 115 |
| 2021 | 296 | 58 | 2 | 27 | 160 |
| 2022 | 323 | 34 | 0 | 23 | 128 |
| 2023 | 176 | 169 | 1 | 50 | 170 |
| 2024 | 52 | 35 | 0 | 46 | 74 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Great Falls, MT (46).
More Air Quality Data
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Worst Air Quality
Counties and metros with the most unhealthy air days.
All Metro Areas
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Best and Worst City Air
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Air Quality Guides
Frequently Asked Questions
What is the air quality in the Great Falls, MT metro area? ▼
How many unhealthy air days does Great Falls, MT have? ▼
Is air quality in Great Falls, MT getting better or worse? ▼
What does AQI 46 mean for health? ▼
What is the 90th percentile AQI for Great Falls, MT? ▼
How does Great Falls, MT compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. 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 files (metro-level) · 2020–2025
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Every figure on PlainAirData 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.