Urban Honolulu, HI

EPA AQS → · NOAA →

Metro area air quality from EPA Air Quality System (2024). 366 days monitored. Median AQI: 31 (Good).

Insights: Urban Honolulu, HI metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 31 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 360 Good days (98%), 6 Moderate (2%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 41 while the highest single-day reading hit 85 (Moderate). Metro residents averaged roughly 29.5 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by -3 and the median AQI moved +3 points, which classifies the multi-year trajectory as stable. 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 Butte-Silver Bow, MT (70.5% good, AQI 31); Dyersburg, TN (82.4% good, AQI 31); Lewiston-Auburn, ME (92.6% good, AQI 31).

Air Quality Summary

Median AQI

31

Good

Good Days

98.4%

360 of 366 days

Max AQI

85

Moderate

Health Grade

Excellent

90th pct: 41

AQI Day Breakdown (2024)

Distribution of 366 monitored days across EPA AQI categories.

Good

360

98%

Moderate

6

2%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Urban Honolulu, HI metro area's air quality is rated Excellent based on 98.4% 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.

5-Year Air Quality Trend

Air quality is stable in the Urban Honolulu, HI metro. Best year: 2021 (364 good days).

Year Good Moderate Unhealthy Median AQI
2020 363 3 0 28
2021 364 1 0 28
2022 356 9 0 29
2023 337 27 0 31
2024 360 6 0 31

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Urban Honolulu, HI.

Butte-Silver Bow, MT

AQI 31 · 70.5% good

31

Dyersburg, TN

AQI 31 · 82.4% good

31

Lewiston-Auburn, ME

AQI 31 · 92.6% good

31

Pahrump, NV

AQI 31 · 87.2% good

31

Athens, TN

AQI 32 · 78.9% good

32

Clearlake, CA

AQI 32 · 99.5% good

32

Related Environmental & Health Data

Explore related data for the Urban Honolulu, HI area from other federal sources.

🏭

PlainEnviro — EPA Facilities

EPA environmental compliance data for regulated facilities. 5-year violation trends.

🏥

PlainHealth — Mortality Data

CDC NCHS leading causes of death. 19 years of mortality data by cause.

🌡️

PlainClimate — Climate Normals

NOAA 30-year climate normals. Temperature, precipitation, humidity.

⚠️

PlainHazard — Natural Disasters

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 Urban Honolulu, HI metro area? ▼
The Urban Honolulu, HI metro area has a median Air Quality Index (AQI) of 31, rated "Good." 98.4% of monitored days (360 out of 366) had good air quality in 2024.
How many unhealthy air days does Urban Honolulu, HI have? ▼
In 2024, the Urban Honolulu, HI metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 85.
Is air quality in Urban Honolulu, HI getting better or worse? ▼
Air quality in the Urban Honolulu, HI metro is stable based on 5-year trends (2020-2024). Best year: 2021 with 364 good days. Worst year: 2023 with 337 good days.
What does AQI 31 mean for health? ▼
An AQI of 31 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 Urban Honolulu, HI? ▼
The 90th percentile AQI for the Urban Honolulu, HI metro area is 41, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 85 (Moderate).
How does Urban Honolulu, HI compare to other metro areas? ▼
The Urban Honolulu, HI metro has 98.4% good air days. Similar metros: Butte-Silver Bow, MT (70.5% good), Dyersburg, TN (82.4% good), Lewiston-Auburn, ME (92.6% 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