Metro area air quality · 2025

St. Joseph, MO-KS

Median AQI 47 (Good). 56.2% of monitored days rated Good across this metro's EPA monitoring network.

47
Median AQI
56.2%
Good-air days
1
Unhealthy days
19%
Cleaner than US metros

St. Joseph, MO-KS posted a 2025 median AQI of 47 (Good) with 56.2% Good days

According to the U.S. EPA Air Quality System, the St. Joseph, MO-KS CBSA recorded a median AQI of 47 across 365 monitored days in 2025, with 56.2% rated Good and 1 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 St. Joseph, MO-KS CBSA's 56.2% Good-day share places it cleaner than 19% of US metros in 2025.
Closest median-AQI peer
Charleston-North Charleston, SC (60.3% Good, median AQI 47) is the closest nationwide median-AQI peer to St. Joseph, MO-KS.
2020–2025 Good-day shift
St. Joseph, MO-KS's Good-day share moved -10.1 points from 2020 to 2025 (median AQI +3).
Median AQI
Median AQI: 47

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

St. Joseph, MO-KS lands in the lower Good-day tercile (56.2% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, among the more polluted US metros, with a median AQI of 47 and 56.2% of 365 monitored days in the Good band.

47
median AQI · Good
56.2%
days rated Good
19%
cleaner than US metros
256
worst single reading

1 day reached Unhealthy or worse across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • St. Joseph, MO-KS metro's peak single-day AQI rose from 100 to 256 between the 2024 and 2025 EPA annual releases, a change of +156 points.

Compared against 359 monitored days in 2024 and 363 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

St. Joseph, MO-KS lands in the lower Good-day tercile (56.2% Good), a thinner clean-air share than most CBSA peers here. Signature read: 56.2% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 47 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 205 Good (56%), 158 Moderate (43%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 65; the highest single-day reading hit 256 (Very Unhealthy).

Across 2020–2025, Good-day share shifted -10.1 points and median AQI moved +3 (worsening). The annual record contains 1 day at Unhealthy or worse. Metros with comparable AQI profiles include Charleston-North Charleston, SC (60.3% good, AQI 47); Columbia, SC (58.1% good, AQI 47); Corsicana, TX (59.2% good, AQI 47).

Health effects of air pollution →

Air Quality Summary

Median AQI

47

Good

Good Days

56.2%

205 of 365 days

Max AQI

256

Very Unhealthy

Health Grade

Moderate

90th pct: 65

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

205

56%

Moderate

158

43%

USG

1

0%

Unhealthy

0

0%

Very Unhealthy

1

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The St. Joseph, MO-KS metro area's air quality is rated Moderate based on 56.2% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.

Air quality reached unhealthy levels on 1 days in 2025 (0 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 St. Joseph, MO-KS metro compare?

How St. Joseph, MO-KS compares

Good-day share worse than typical
St. Joseph, MO-KS 56.2%
Charleston-North Charleston, SC 60.3%
Typical US metro 70.6%
Median AQI worse than typical
St. Joseph, MO-KS 47
Charleston-North Charleston, SC 47
Typical US metro 41
Unhealthy days / yr about typical
St. Joseph, MO-KS 1
Charleston-North Charleston, SC 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the St. Joseph, MO-KS metro. Highest Good-day share: 2020 (66.6%, 243 of 365 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 243 122 0 44
2021 230 132 0 44
2022 227 135 0 46
2023 182 175 0 51
2024 202 157 0 48
2025 205 158 0 47

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near St. Joseph, MO-KS (47).

Charleston-North Charleston, SC

Median AQI 47 · 60.3% Good-day share

47

Columbia, SC

Median AQI 47 · 58.1% Good-day share

47

Corsicana, TX

Median AQI 47 · 59.2% Good-day share

47

Dayton, OH

Median AQI 47 · 57.0% Good-day share

47

Evansville, IN-KY

Median AQI 47 · 57.5% Good-day share

47

Farmington, NM

Median AQI 47 · 68.0% Good-day share

47

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to St. Joseph, MO-KS's 1 (independent of median AQI).

Ann Arbor, MI

1 unhealthy-or-worse days · median AQI 41

41

Bangor, ME

1 unhealthy-or-worse days · median AQI 33

33

Baraboo, WI

1 unhealthy-or-worse days · median AQI 35

35

Bartlesville, OK

1 unhealthy-or-worse days · median AQI 44

44

Beaumont-Port Arthur, TX

1 unhealthy-or-worse days · median AQI 52

52

Beaver Dam, WI

1 unhealthy-or-worse days · median AQI 40

40

Frequently Asked Questions

How many unhealthy air days does St. Joseph, MO-KS have? ▼
In 2025, the St. Joseph, MO-KS metro area recorded 1 unhealthy air days (0 Unhealthy, 1 Very Unhealthy, 0 Hazardous). The maximum AQI reached 256.
What is the air quality in the St. Joseph, MO-KS metro area? ▼
The St. Joseph, MO-KS metro area has a median Air Quality Index (AQI) of 47, rated "Good." 56.2% of monitored days (205 out of 365) had good air quality in 2025.
Is air quality in St. Joseph, MO-KS getting better or worse? ▼
Air quality in the St. Joseph, MO-KS metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 66.6% (243 of 365 days). Lowest qualifying Good-day share: 2023 at 51.0% (182 of 357 days).
What does AQI 47 mean for health? ▼
An AQI of 47 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
How does St. Joseph, MO-KS compare to other metro areas? ▼
The St. Joseph, MO-KS metro has 56.2% good air days. Similar metros: Charleston-North Charleston, SC (60.3% good), Columbia, SC (58.1% good), Corsicana, TX (59.2% good).
What is the 90th percentile AQI for St. Joseph, MO-KS? ▼
The 90th percentile AQI for the St. Joseph, MO-KS metro area is 65, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 256 (Very Unhealthy).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for St. Joseph, MO-KS, 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, St. Joseph, MO-KS · 2020–2025