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.

Compiled by PlainAirData · August 23, 2026

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

The Shelton, WA metro runs good on the EPA scale, cleaner than most US metros, a median AQI of 23 with 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.

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.

Insights: Shelton, WA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 23 over 365 measured days in 2025, which corresponds to a Good band and a Excellent metro-wide health grade. The monitored-day split lands at 330 Good days (90%), 34 Moderate (9%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 48 while the highest single-day reading hit 159 (Unhealthy). Metro residents averaged roughly 27.1 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +1.3 points and the median AQI moved +0 points, which classifies the multi-year trajectory as stable. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. 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

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

USG

Unhealthy

Very Unhealthy

Hazardous

Health Impact Assessment

Excellent

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

Compare against

Good-day share better than typical

Shelton, WA 90.4%

Bend-Redmond, OR 89.3%

Typical US metro 70.6%

Median AQI better than typical

Shelton, WA 23

Bend-Redmond, OR 23

Typical US metro 41

Unhealthy days / yr about typical

Shelton, WA 1

Bend-Redmond, OR 1

Typical US metro 1

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

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the Shelton, WA metro area? ▼

The Shelton, WA metro area has a median Air Quality Index (AQI) of 23, rated "Good." 90.4% of monitored days (330 out of 365) had good air quality in 2025.

How many unhealthy air days does Shelton, WA have? ▼

In 2025, the Shelton, WA metro area recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 159.

Is air quality in Shelton, WA getting better or worse? ▼

Air quality in the Shelton, WA metro is stable across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2021 at 93.9% (339 of 361 days). Lowest qualifying Good-day share: 2022 at 83.4% (302 of 362 days).

What does AQI 23 mean for health? ▼

An AQI of 23 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 Shelton, WA? ▼

The 90th percentile AQI for the Shelton, WA metro area is 48, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 159 (Unhealthy).

How does Shelton, WA compare to other metro areas? ▼

The Shelton, WA metro has 90.4% good air days. Similar metros: Bend-Redmond, OR (89.3% good), Cañon City, CO (93.4% good), Juneau, AK (84.3% good).

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 Accessed 2026-07-06

Send the source-year summary or download its ready-to-use data card.

X Facebook LinkedIn WhatsApp Email

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.