Metro area air quality · 2024

Aberdeen, WA

Median AQI 20 (Good). 96.5% of monitored days rated Good across this metro's EPA monitoring network.

20
Median AQI
96.5%
Good-air days
0
Unhealthy days
95%
Cleaner than US metros

Aggregated from EPA Air Quality System (2024), 366 monitored days. EPA AQS → · NOAA →

Insights: Aberdeen, WA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 20 over 366 measured days in 2024, which corresponds to a Good band and a Excellent metro-wide health grade. The monitored-day split lands at 353 Good days (96%), 13 Moderate (4%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 36 while the highest single-day reading hit 64 (Moderate). Metro residents averaged roughly 28.9 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by +23 and the median AQI moved -7 points, which classifies the multi-year trajectory as improving. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Pullman, WA (84.7% good, AQI 20); Winona, MN (93.4% good, AQI 20); Bremerton-Silverdale, WA (97.2% good, AQI 19).

Air Quality Summary

Median AQI

20

Good

Good Days

96.5%

353 of 366 days

Max AQI

64

Moderate

Health Grade

Excellent

90th pct: 36

AQI Day Breakdown (2024)

Distribution of 366 monitored days across EPA AQI categories.

Good

353

96%

Moderate

13

4%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Aberdeen, WA metro area's air quality is rated Excellent based on 96.5% good air days. No unhealthy air days were recorded in 2024.

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

How does the Aberdeen, WA metro compare?

How Aberdeen, WA compares

Good-day share better than US avg
Aberdeen, WA 96.5%
Pullman, WA 84.7%
US average 70.2%
Median AQI better than US avg
Aberdeen, WA 20
Pullman, WA 20
US average 41
Unhealthy days / yr better than US avg
Aberdeen, WA 0
Pullman, WA 0
US average 1

5-Year Air Quality Trend

Air quality is improving in the Aberdeen, WA metro. Best year: 2024 (353 good days).

Year Good Moderate Unhealthy Median AQI
2020 330 28 2 27
2021 347 18 0 26
2022 340 24 0 22
2023 339 26 0 23
2024 353 13 0 20

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Aberdeen, WA.

Pullman, WA

AQI 20 · 84.7% good

20

Winona, MN

AQI 20 · 93.4% good

20

Bremerton-Silverdale, WA

AQI 19 · 97.2% good

19

Hailey, ID

AQI 19 · 86.3% good

19

Hilo, HI

AQI 21 · 97.0% good

21

Kahului-Wailuku-Lahaina, HI

AQI 21 · 99.7% good

21

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Health Effects of Air Pollution

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Frequently Asked Questions

What is the air quality in the Aberdeen, WA metro area? ▼
The Aberdeen, WA metro area has a median Air Quality Index (AQI) of 20, rated "Good." 96.5% of monitored days (353 out of 366) had good air quality in 2024.
How many unhealthy air days does Aberdeen, WA have? ▼
In 2024, the Aberdeen, WA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 64.
Is air quality in Aberdeen, WA getting better or worse? ▼
Air quality in the Aberdeen, WA metro is improving based on 5-year trends (2020-2024). Best year: 2024 with 353 good days. Worst year: 2020 with 330 good 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 Aberdeen, WA? ▼
The 90th percentile AQI for the Aberdeen, WA metro area is 36, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 64 (Moderate).
How does Aberdeen, WA compare to other metro areas? ▼
The Aberdeen, WA metro has 96.5% good air days. Similar metros: Pullman, WA (84.7% good), Winona, MN (93.4% good), Bremerton-Silverdale, WA (97.2% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.

Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.

Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.

Read our methodology , how this data is sourced, computed, and verified.

Source: U.S. EPA, AirNow / AQS Air Quality Index readings and pollutant concentrations · 2025