Metro area air quality · 2024

Billings, MT

Median AQI 39 (Good). 76.2% of monitored days rated Good across this metro's EPA monitoring network.

39
Median AQI
76.2%
Good-air days
0
Unhealthy days
55%
Cleaner than US metros

Aggregated from EPA Air Quality System (2024), 357 monitored days. EPA AQS → · NOAA →

Insights: Billings, MT metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 39 over 357 measured days in 2024, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 272 Good days (76%), 84 Moderate (24%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 61 while the highest single-day reading hit 105 (USG). Metro residents averaged roughly 22.9 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by -32 and the median AQI moved +8 points, which classifies the multi-year trajectory as worsening. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Alexandria, LA (70.3% good, AQI 39); Bend-Redmond, OR (70.5% good, AQI 39); Brunswick, GA (78.1% good, AQI 39).

Air Quality Summary

Median AQI

39

Good

Good Days

76.2%

272 of 357 days

Max AQI

105

USG

Health Grade

Good

90th pct: 61

AQI Day Breakdown (2024)

Distribution of 357 monitored days across EPA AQI categories.

Good

272

76%

Moderate

84

24%

USG

1

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Billings, MT metro area's air quality is rated Good based on 76.2% 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 Billings, MT metro compare?

How Billings, MT compares

Good-day share better than US avg
Billings, MT 76.2%
Alexandria, LA 70.3%
US average 70.2%
Median AQI better than US avg
Billings, MT 39
Alexandria, LA 39
US average 41
Unhealthy days / yr better than US avg
Billings, MT 0
Alexandria, LA 0
US average 1

5-Year Air Quality Trend

Air quality is worsening in the Billings, MT metro. Best year: 2022 (307 good days).

Year Good Moderate Unhealthy Median AQI
2020 304 57 1 31
2021 212 118 1 40
2022 307 56 1 32
2023 306 47 1 29
2024 272 84 0 39

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Billings, MT.

Alexandria, LA

AQI 39 · 70.3% good

39

Bend-Redmond, OR

AQI 39 · 70.5% good

39

Brunswick, GA

AQI 39 · 78.1% good

39

College Station-Bryan, TX

AQI 39 · 65.7% good

39

Columbia, MO

AQI 39 · 94.2% good

39

Duluth, MN-WI

AQI 39 · 78.1% good

39

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Air Quality Guides

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Health Effects of Air Pollution

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Frequently Asked Questions

What is the air quality in the Billings, MT metro area? ▼
The Billings, MT metro area has a median Air Quality Index (AQI) of 39, rated "Good." 76.2% of monitored days (272 out of 357) had good air quality in 2024.
How many unhealthy air days does Billings, MT have? ▼
In 2024, the Billings, MT metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 105.
Is air quality in Billings, MT getting better or worse? ▼
Air quality in the Billings, MT metro is worsening based on 5-year trends (2020-2024). Best year: 2022 with 307 good days. Worst year: 2021 with 212 good days.
What does AQI 39 mean for health? ▼
An AQI of 39 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Billings, MT? ▼
The 90th percentile AQI for the Billings, MT metro area is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 105 (USG).
How does Billings, MT compare to other metro areas? ▼
The Billings, MT metro has 76.2% good air days. Similar metros: Alexandria, LA (70.3% good), Bend-Redmond, OR (70.5% good), Brunswick, GA (78.1% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.

Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.

Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.

Read our methodology , how this data is sourced, computed, and verified.

Source: U.S. EPA, AirNow / AQS Air Quality Index readings and pollutant concentrations · 2025