Metro area air quality · 2025
Bismarck, ND
Median AQI 40 (Good). 76.7% of monitored days rated Good across this metro's EPA monitoring network.
- 40
- Median AQI
- 76.7%
- Good-air days
- 4
- Unhealthy days
- 60%
- Cleaner than US metros
Bismarck, ND posted a 2025 median AQI of 40 (Good) with 76.7% Good days
According to the U.S. EPA Air Quality System, the Bismarck, ND CBSA recorded a median AQI of 40 across 365 monitored days in 2025, with 76.7% rated Good and 4 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 Bismarck, ND CBSA's 76.7% Good-day share places it cleaner than 60% of US metros in 2025.
- Closest median-AQI peer
- Altoona, PA (76.9% Good, median AQI 40) is the closest nationwide median-AQI peer to Bismarck, ND.
- 2020–2025 Good-day shift
- Bismarck, ND's Good-day share moved -1.7 points from 2020 to 2025 (median AQI +0).
- Median AQI
- Median AQI: 40
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Bismarck, ND's peak reading 242 is in the upper max-AQI tercile among CBSA metros here. On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 40 and 76.7% of 365 monitored days in the Good band.
- 40
- median AQI · Good
- 76.7%
- days rated Good
- 60%
- cleaner than US metros
- 242
- worst single reading
4 days reached Unhealthy or worse across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Bismarck, ND metro's peak single-day AQI rose from 174 to 242 between the 2024 and 2025 EPA annual releases, a change of +68 points.
- Bismarck, ND metro's Good-day share rose from 74.8% to 78.9% between the 2024 and 2025 EPA annual releases, a change of +4.1 percentage points.
- Bismarck, ND metro's Unhealthy-category days rose from 2 to 3 between the 2024 and 2025 EPA annual releases, a change of +1 days.
Bismarck, ND's peak reading 242 is in the upper max-AQI tercile among CBSA metros here. Signature read: peak AQI 242 (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 40 over 365 measured days in 2025 (Good / Good). The monitored-day split lands at 280 Good (77%), 72 Moderate (20%), and 9 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 61; the highest single-day reading hit 242 (Very Unhealthy).
Across 2020–2025, Good-day share shifted -1.7 points and median AQI moved +0 (stable). The annual record contains 4 days at Unhealthy or worse. Metros with comparable AQI profiles include Altoona, PA (76.9% good, AQI 40); Beaver Dam, WI (72.3% good, AQI 40); Cape Coral-Fort Myers, FL (76.4% good, AQI 40).
Air Quality Summary
Median AQI
40
Good
Good Days
76.7%
280 of 365 days
Max AQI
242
Very Unhealthy
Health Grade
Good
90th pct: 61
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
280
77%
Moderate
72
20%
USG
9
2%
Unhealthy
3
1%
Very Unhealthy
1
0%
Hazardous
0
0%
Health Impact Assessment
The Bismarck, ND metro area's air quality is rated Good based on 76.7% good air days. There were 4 unhealthy days in 2025 when outdoor activity should be limited.
Air quality reached unhealthy levels on 4 days in 2025 (3 Unhealthy, 1 Very Unhealthy). Sensitive groups, including people with asthma, COPD, cardiovascular conditions, children, and adults over 65, should review the daily breakdown and follow local advisories.
Sensitive group advisory
People with asthma, COPD, heart disease, children, pregnant women, and adults 65+ should follow EPA AQI alerts daily and limit outdoor exertion when AQI exceeds 100. Real-time conditions: airnow.gov.
How does the Bismarck, ND metro compare?
How Bismarck, ND compares
5-Year Air Quality Trend
Air quality is stable in the Bismarck, ND metro. Highest Good-day share: 2020 (80.6%, 295 of 366 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 295 | 71 | 0 | 40 | 77 |
| 2021 | 234 | 112 | 8 | 43 | 183 |
| 2022 | 246 | 119 | 0 | 43 | 99 |
| 2023 | 210 | 129 | 9 | 46 | 323 |
| 2024 | 267 | 88 | 2 | 40 | 174 |
| 2025 | 280 | 72 | 3 | 40 | 242 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Bismarck, ND (40).
Altoona, PA
Median AQI 40 · 76.9% Good-day share
Beaver Dam, WI
Median AQI 40 · 72.3% Good-day share
Cape Coral-Fort Myers, FL
Median AQI 40 · 76.4% Good-day share
College Station-Bryan, TX
Median AQI 40 · 68.5% Good-day share
Fallon, NV
Median AQI 40 · 85.2% Good-day share
Fayetteville-Springdale-Rogers, AR-MO
Median AQI 40 · 83.3% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Bismarck, ND's 4 (independent of median AQI).
Bakersfield, CA
4 unhealthy-or-worse days · median AQI 70
Bishop, CA
4 unhealthy-or-worse days · median AQI 55
Dickinson, ND
4 unhealthy-or-worse days · median AQI 38
New York-Newark-Jersey City, NY-NJ-PA
4 unhealthy-or-worse days · median AQI 53
St. Louis, MO-IL
4 unhealthy-or-worse days · median AQI 56
Wausau, WI
4 unhealthy-or-worse days · median AQI 36
Frequently Asked Questions
What is the 90th percentile AQI for Bismarck, ND? ▼
How many unhealthy air days does Bismarck, ND have? ▼
What is the air quality in the Bismarck, ND metro area? ▼
Is air quality in Bismarck, ND getting better or worse? ▼
What does AQI 40 mean for health? ▼
How does Bismarck, ND compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Bismarck, ND, 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, Bismarck, ND · 2020–2025