State air quality · 2025
Hawaii Air Quality Ranking
Across 3 monitored counties, the typical county in Hawaii posts a median AQI of 27 (Good) and 93.8% of monitored days were rated Good, from EPA AQS.
- 27
- Avg median AQI
- 93.8%
- Good-air days
- 3
- Counties monitored
- 98%
- Cleaner than US states
Hawaii's typical county median AQI is 27 (Good) across 3 monitored counties
According to the U.S. EPA Air Quality System, Hawaii monitors 3 counties with a day-weighted Good-day share of 93.8%. Cleanest: Maui County (98.1% Good). Most polluted: Hawaii County (86.0%). These are annual summaries, not live AirNow readings.
Data source EPA Air Quality System (AQS)
- Cleaner than US states
- Hawaii's day-weighted Good-day share of 93.8% places it cleaner than 98% of US states.
- In-state spread
- Within Hawaii, Maui County leads at 98.1% Good days while Hawaii County sits at 86.0% across 3 monitored counties.
- 2024→2025 release
- Hawaii's Good-day share moved -4.6 points vs the 2024 EPA annual release.
- Typical median AQI
- Typical median AQI: 27
Verify with AirNow → · EPA AQS →
EPA state monitoring brief
AQS state key HAWAII
Hawaii · 2025 EPA AQS · 3 counties · med AQI 27 · 93.8% Good · Maui→Hawaii spread
- GOOD 27 Median AQI · Good
- SHARE 93.8% Good-day share
- COUNT 3 Counties monitored
- UNH 0 Unhealthy+ days
- RANK 98% Cleaner than states
- PM25 79.2% Main pollutant share
Hawaii's 93.8% Good-day share is cleaner than 98% of monitored US states; Maui and Hawaii County bracket the in-state range. Open Maui County →
According to EPA AQS annual summaries on PlainAirData, Hawaii is #1 of 52 by day-weighted good-day share (93.8%) at mean county median-AQI #4 (27.3) ≠ Alaska #1 lowest mean county median AQI (20.3, good-day share #8).
Data updated August 2026
What changed, what drives it, and how thick is the sample
Three derived views WPR-style word count does not substitute for: release-over-release movement from county annual rows, the EPA main-pollutant day mix, and how many counties sit below the 100-day ranking floor.
Release change
93.8%
Good-day share in 2025, down 4.6 percentage points vs 2024. County-mean median AQI 27, 3.0 points higher (worse) than 2024.
Pollutant mix
PM2.5
Main driver on 79.2% of pollutant-assigned days.
- PM2.5 79.2%
- Ozone 20.7%
- PM10 0.1%
Monitoring coverage
363
Average monitored days per county in the latest release. Every monitored county clears the 100-day ranking floor.
Counties Monitored
3
Good Days %
93.8%
Avg Median AQI
27
Total Unhealthy Days
0
Best Air Quality
Maui County
Worst Air Quality
Hawaii County
Where Hawaii sits nationally
COUNT-derived placement among 52 US states with at least 365 monitored days in the latest county release. Hawaii's day-weighted Good-day share is 93.8% - cleaner than 98% of that comparison set.
Hawaii Good-day share vs. every US state
Day-weighted share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
93.8% Cleaner than 98% higher than 98% of 52 US states
Each bar is a band; taller bars hold more US states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Which counties in Hawaii have the cleanest and most polluted air?
Cleanest counties in Hawaii
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025. See our methodology for how AQI and median figures are computed.
Coverage: 3 counties in Hawaii with active monitoring stations. Unmonitored counties are not represented.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files, aggregated to the state level · 2020–2025
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.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.