Metro area air quality · 2024

Longview, WA

Median AQI 22 (Good). 95.4% of monitored days rated Good across this metro's EPA monitoring network.

22
Median AQI
95.4%
Good-air days
0
Unhealthy days
94%
Cleaner than US metros

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

Insights: Longview, WA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 22 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 349 Good days (95%), 17 Moderate (5%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 41 while the highest single-day reading hit 67 (Moderate). Metro residents averaged roughly 28.6 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by +18 and the median AQI moved +1 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 Centralia, WA (93.3% good, AQI 22); Gardnerville Ranchos, NV (90.1% good, AQI 22); Elko, NV (87.1% good, AQI 23).

Air Quality Summary

Median AQI

22

Good

Good Days

95.4%

349 of 366 days

Max AQI

67

Moderate

Health Grade

Excellent

90th pct: 41

AQI Day Breakdown (2024)

Distribution of 366 monitored days across EPA AQI categories.

Good

349

95%

Moderate

17

5%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Longview, WA metro area's air quality is rated Excellent based on 95.4% 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 Longview, WA metro compare?

How Longview, WA compares

Good-day share better than US avg
Longview, WA 95.4%
Centralia, WA 93.3%
US average 70.2%
Median AQI better than US avg
Longview, WA 22
Centralia, WA 22
US average 41
Unhealthy days / yr better than US avg
Longview, WA 0
Centralia, WA 0
US average 1

5-Year Air Quality Trend

Air quality is improving in the Longview, WA metro. Best year: 2021 (355 good days).

Year Good Moderate Unhealthy Median AQI
2020 331 26 3 21
2021 355 10 0 21
2022 316 45 0 21
2023 323 42 0 22
2024 349 17 0 22

Metros with Similar Air Quality

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

Centralia, WA

AQI 22 · 93.3% good

22

Gardnerville Ranchos, NV

AQI 22 · 90.1% good

22

Elko, NV

AQI 23 · 87.1% good

23

Ellensburg, WA

AQI 23 · 87.4% good

23

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 Longview, WA metro area? ▼
The Longview, WA metro area has a median Air Quality Index (AQI) of 22, rated "Good." 95.4% of monitored days (349 out of 366) had good air quality in 2024.
How many unhealthy air days does Longview, WA have? ▼
In 2024, the Longview, WA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 67.
Is air quality in Longview, WA getting better or worse? ▼
Air quality in the Longview, WA metro is improving based on 5-year trends (2020-2024). Best year: 2021 with 355 good days. Worst year: 2022 with 316 good days.
What does AQI 22 mean for health? ▼
An AQI of 22 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 Longview, WA? ▼
The 90th percentile AQI for the Longview, WA metro area is 41, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 67 (Moderate).
How does Longview, WA compare to other metro areas? ▼
The Longview, WA metro has 95.4% good air days. Similar metros: Centralia, WA (93.3% good), Gardnerville Ranchos, NV (90.1% good), Elko, NV (87.1% 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