Metro area air quality · 2025

Centralia, WA

Median AQI 20 (Good). 91.3% of monitored days rated Good across this metro's EPA monitoring network.

Compiled by PlainAirData · August 23, 2026

20
Median AQI: 91.3%
Good-air days: 0
Unhealthy days: 89%
Cleaner than US metros

Centralia, WA posted a 2025 median AQI of 20 (Good) with 91.3% Good days

According to the U.S. EPA Air Quality System, the Centralia, WA CBSA recorded a median AQI of 20 across 323 monitored days in 2025, with 91.3% rated Good and 0 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 Centralia, WA CBSA's 91.3% Good-day share places it cleaner than 89% of US metros in 2025.
Closest median-AQI peer: Kahului-Wailuku-Lahaina, HI (98.1% Good, median AQI 21) is the closest nationwide median-AQI peer to Centralia, WA.
2020–2025 Good-day shift: Centralia, WA's Good-day share moved -2.7 points from 2020 to 2025 (median AQI -5).
Median AQI: Median AQI: 20

Aggregated from EPA Air Quality System (2025), 323 monitored days. EPA AQS →

The verdict

The Centralia, WA metro runs good on the EPA scale, cleaner than most US metros, a median AQI of 20 with 91.3% of 323 monitored days in the Good band.

20
median AQI · Good: 91.3%
days rated Good: 89%
cleaner than US metros: 74
worst single reading

No day crossed into the Unhealthy tier across the metro's monitors in 2025.

Centralia, WA metro's peak single-day AQI fell from 129 to 74 between the 2024 and 2025 EPA annual releases, a change of -55 points.
Centralia, WA metro's Good-day share fell from 93.6% to 91.3% between the 2024 and 2025 EPA annual releases, a change of -2.3 percentage points.

Insights: Centralia, WA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 20 over 323 measured days in 2025, which corresponds to a Good band and a Excellent metro-wide health grade. The monitored-day split lands at 295 Good days (91%), 28 Moderate (9%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 48 while the highest single-day reading hit 74 (Moderate). Metro residents averaged roughly 27.4 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 -2.7 points and the median AQI moved -5 points, which classifies the multi-year trajectory as stable. The metro recorded no Unhealthy-tier days in this annual dataset. Metros with comparable AQI profiles include Kahului-Wailuku-Lahaina, HI (98.1% good, AQI 21); Marquette, MI (82.4% good, AQI 19); Othello, WA (90.5% good, AQI 21).

Air Quality Summary

Median AQI

Good

Good Days

91.3%

295 of 323 days

Max AQI

Moderate

Health Grade

Excellent

90th pct: 48

AQI Day Breakdown (2025)

Distribution of 323 monitored days across EPA AQI categories.

Good

295

91%

Moderate

USG

Unhealthy

Very Unhealthy

Hazardous

Health Impact Assessment

Excellent

The Centralia, WA metro area's air quality is rated Excellent based on 91.3% good air days. No unhealthy air days were recorded in 2025.

Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.

How does the Centralia, WA metro compare?

How Centralia, WA compares

Compare against

Good-day share better than typical

Centralia, WA 91.3%

Kahului-Wailuku-Lahaina, HI 98.1%

Typical US metro 70.6%

Median AQI better than typical

Centralia, WA 20

Kahului-Wailuku-Lahaina, HI 21

Typical US metro 41

Unhealthy days / yr better than typical

Centralia, WA 0

Kahului-Wailuku-Lahaina, HI 0

Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Centralia, WA metro. Highest Good-day share: 2020 (94.0%, 314 of 334 monitored days).

Year	Good	Moderate	Unhealthy	Median AQI	Max AQI
2020	314	20	0	25	258
2021	328	22	0	23	71
2022	285	70	3	26	198
2023	314	46	1	25	159
2024	336	23	0	22	129
2025	295	28	0	20	74

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Centralia, WA (20).

Kahului-Wailuku-Lahaina, HI

Median AQI 21 · 98.1% Good-day share

Marquette, MI

Median AQI 19 · 82.4% Good-day share

Othello, WA

Median AQI 21 · 90.5% Good-day share

Palatka, FL

Median AQI 21 · 95.6% 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 Centralia, WA's 0 (independent of median AQI).

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

Albany-Schenectady-Troy, NY

0 unhealthy-or-worse days · median AQI 41

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 Centralia, WA metro area? ▼

The Centralia, WA metro area has a median Air Quality Index (AQI) of 20, rated "Good." 91.3% of monitored days (295 out of 323) had good air quality in 2025.

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

In 2025, the Centralia, WA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 74.

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

Air quality in the Centralia, 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: 2020 at 94.0% (314 of 334 days). Lowest qualifying Good-day share: 2022 at 79.6% (285 of 358 days).

What does AQI 20 mean for health? ▼

An AQI of 20 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 Centralia, WA? ▼

The 90th percentile AQI for the Centralia, WA metro area is 48, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 74 (Moderate).

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

The Centralia, WA metro has 91.3% good air days. Similar metros: Kahului-Wailuku-Lahaina, HI (98.1% good), Marquette, MI (82.4% good), Othello, WA (90.5% 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.

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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.