Mount Vernon-Anacortes, WA

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Metro area air quality from EPA Air Quality System (2024). 366 days monitored. Median AQI: 26 (Good).

Insights: Mount Vernon-Anacortes, WA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 26 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 357 Good days (98%), 9 Moderate (2%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 41 while the highest single-day reading hit 59 (Moderate). Metro residents averaged roughly 29.3 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by +91 and the median AQI moved +5 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 Anchorage, AK (77.6% good, AQI 26); Branson, MO (88.9% good, AQI 26); Dodge City, KS (86.6% good, AQI 26).

Air Quality Summary

Median AQI

26

Good

Good Days

97.5%

357 of 366 days

Max AQI

59

Moderate

Health Grade

Excellent

90th pct: 41

AQI Day Breakdown (2024)

Distribution of 366 monitored days across EPA AQI categories.

Good

357

98%

Moderate

9

2%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Mount Vernon-Anacortes, WA metro area's air quality is rated Excellent based on 97.5% 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.

5-Year Air Quality Trend

Air quality is improving in the Mount Vernon-Anacortes, WA metro. Best year: 2024 (357 good days).

Year Good Moderate Unhealthy Median AQI
2020 266 6 0 21
2021 296 17 0 28
2022 313 47 1 33
2023 336 29 0 30
2024 357 9 0 26

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Mount Vernon-Anacortes, WA.

Anchorage, AK

AQI 26 · 77.6% good

26

Branson, MO

AQI 26 · 88.9% good

26

Dodge City, KS

AQI 26 · 86.6% good

26

Moses Lake, WA

AQI 26 · 86.9% good

26

Olympia-Tumwater, WA

AQI 26 · 93.4% good

26

Albany, OR

AQI 25 · 87.4% good

25

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FEMA disaster declarations. Wildfire, flood, and storm history affecting air quality. FEMA.gov →

Air Quality Guides

Learn more about air quality monitoring, pollutants, and health impacts.

Understanding AQI

What each AQI level means and who is most at risk.

Best & Worst City Air Quality

Metro area air quality rankings and what drives urban pollution.

Health Effects of Air Pollution

How PM2.5 and ozone exposure affects respiratory and cardiovascular health.

Frequently Asked Questions

What is the air quality in the Mount Vernon-Anacortes, WA metro area? ▼
The Mount Vernon-Anacortes, WA metro area has a median Air Quality Index (AQI) of 26, rated "Good." 97.5% of monitored days (357 out of 366) had good air quality in 2024.
How many unhealthy air days does Mount Vernon-Anacortes, WA have? ▼
In 2024, the Mount Vernon-Anacortes, WA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 59.
Is air quality in Mount Vernon-Anacortes, WA getting better or worse? ▼
Air quality in the Mount Vernon-Anacortes, WA metro is improving based on 5-year trends (2020-2024). Best year: 2024 with 357 good days. Worst year: 2020 with 266 good days.
What does AQI 26 mean for health? ▼
An AQI of 26 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 Mount Vernon-Anacortes, WA? ▼
The 90th percentile AQI for the Mount Vernon-Anacortes, WA metro area is 41, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 59 (Moderate).
How does Mount Vernon-Anacortes, WA compare to other metro areas? ▼
The Mount Vernon-Anacortes, WA metro has 97.5% good air days. Similar metros: Anchorage, AK (77.6% good), Branson, MO (88.9% good), Dodge City, KS (86.6% 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