Metro area air quality · 2025
Shelton, WA
Median AQI 23 (Good). 90.4% of monitored days rated Good across this metro's EPA monitoring network.
- 23
- Median AQI
- 90.4%
- Good-air days
- 1
- Unhealthy days
- 87%
- Cleaner than US metros
Shelton, WA posted a 2025 median AQI of 23 (Good) with 90.4% Good days
According to the U.S. EPA Air Quality System, the Shelton, WA CBSA recorded a median AQI of 23 across 365 monitored days in 2025, with 90.4% 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 Shelton, WA CBSA's 90.4% Good-day share places it cleaner than 87% of US metros in 2025.
- Closest median-AQI peer
- Bend-Redmond, OR (89.3% Good, median AQI 23) is the closest nationwide median-AQI peer to Shelton, WA.
- 2020–2025 Good-day shift
- Shelton, WA's Good-day share moved +1.3 points from 2020 to 2025 (median AQI +0).
- Median AQI
- Median AQI: 23
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Shelton, WA sits in the upper Good-day tercile among EPA CBSA metros on this site (90.4% of 365 monitored days). On the EPA scale the metro runs good, cleaner than most US metros, with a median AQI of 23 and 90.4% of 365 monitored days in the Good band.
- 23
- median AQI · Good
- 90.4%
- days rated Good
- 87%
- cleaner than US metros
- 159
- 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
- Shelton, WA metro's peak single-day AQI rose from 73 to 159 between the 2024 and 2025 EPA annual releases, a change of +86 points.
- Shelton, WA metro's Good-day share fell from 93.2% to 90.4% between the 2024 and 2025 EPA annual releases, a change of -2.8 percentage points.
- Shelton, WA metro's Unhealthy-category days rose from 0 to 1 between the 2024 and 2025 EPA annual releases, a change of +1 days.
Shelton, WA sits in the upper Good-day tercile among EPA CBSA metros on this site (90.4% of 365 monitored days). Signature read: 90.4% 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 23 over 365 measured days in 2025 (Good / Excellent). The monitored-day split lands at 330 Good (90%), 34 Moderate (9%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 48; the highest single-day reading hit 159 (Unhealthy).
Across 2020–2025, Good-day share shifted +1.3 points and median AQI moved +0 (stable). The annual record contains 1 day at Unhealthy or worse. Metros with comparable AQI profiles include Bend-Redmond, OR (89.3% good, AQI 23); Cañon City, CO (93.4% good, AQI 23); Juneau, AK (84.3% good, AQI 23).
Air Quality Summary
Median AQI
23
Good
Good Days
90.4%
330 of 365 days
Max AQI
159
Unhealthy
Health Grade
Excellent
90th pct: 48
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
330
90%
Moderate
34
9%
USG
0
0%
Unhealthy
1
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Shelton, WA metro area's air quality is rated Excellent based on 90.4% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 0 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 159. Sensitive groups should monitor real-time conditions at AirNow.gov.
How does the Shelton, WA metro compare?
How Shelton, WA compares
5-Year Air Quality Trend
Air quality is stable in the Shelton, WA metro. Highest Good-day share: 2021 (93.9%, 339 of 361 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 312 | 36 | 2 | 23 | 397 |
| 2021 | 339 | 22 | 0 | 22 | 70 |
| 2022 | 302 | 60 | 0 | 23 | 125 |
| 2023 | 313 | 49 | 0 | 24 | 106 |
| 2024 | 341 | 25 | 0 | 21 | 73 |
| 2025 | 330 | 34 | 1 | 23 | 159 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Shelton, WA (23).
Bend-Redmond, OR
Median AQI 23 · 89.3% Good-day share
Cañon City, CO
Median AQI 23 · 93.4% Good-day share
Juneau, AK
Median AQI 23 · 84.3% Good-day share
Pullman, WA
Median AQI 23 · 86.8% Good-day share
Aberdeen, WA
Median AQI 22 · 97.3% Good-day share
Bremerton-Silverdale, WA
Median AQI 22 · 95.5% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Shelton, WA's 1 (independent of median AQI).
Ann Arbor, MI
1 unhealthy-or-worse days · median AQI 41
Bangor, ME
1 unhealthy-or-worse days · median AQI 33
Baraboo, WI
1 unhealthy-or-worse days · median AQI 35
Bartlesville, OK
1 unhealthy-or-worse days · median AQI 44
Beaumont-Port Arthur, TX
1 unhealthy-or-worse days · median AQI 52
Beaver Dam, WI
1 unhealthy-or-worse days · median AQI 40
Frequently Asked Questions
How many unhealthy air days does Shelton, WA have? ▼
What is the air quality in the Shelton, WA metro area? ▼
Is air quality in Shelton, WA getting better or worse? ▼
What does AQI 23 mean for health? ▼
How does Shelton, WA compare to other metro areas? ▼
What is the 90th percentile AQI for Shelton, WA? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Shelton, WA, 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, Shelton, WA · 2020–2025