Median AQI
30
Good
Hawaii · County air quality · 2025
Hawaii County, Hawaii
Median AQI 30 (Good). 81.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 30
- Median AQI
- 81.1%
- Good-air days
- 0
- Unhealthy days
- 56%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Hawaii County's air is good on balance, cleaner than the median US county, a median AQI of 30 with 81.1% of 201 monitored days in the Good band, driven mainly by PM2.5.
- 30
- median AQI · Good
- 81.1%
- days rated Good
- PM2.5
- main pollutant
- 56%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 78.
Data updated July 2026
- Good · 163 d · 81.1%
- Moderate · 38 d · 18.9%
How did Hawaii County's air break down in 2025?
Across 201 monitored days, 163 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 78 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 201 days monitored. Median AQI: 30 (Good).
Insights: Hawaii County, Hawaii. EPA monitors recorded a median Air Quality Index of 30 across 201 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 163 (81%) fell in the Good band (AQI 0–50), 38 (19%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 58, while the worst single-day peak hit 78 (Moderate). Residents averaged about 24.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (201 days). Across the 2020–2025 trend window, good days shifted by -189 and the median AQI moved +7 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 78, moderate but never Unhealthy. Nearby counties show comparable readings: Honolulu (95.0% good, AQI 31); Maui (96.1% good, AQI 22).
Air Quality Summary
Good Days
81.1%
163 of 201 monitored days
6.1pp vs 75% target
Max AQI Recorded
78
Moderate
Health Grade
Good
90th-pct AQI 58
Hawaii County, Good days share 81.1%
National avg
Share of monitored days at AQI 0-50 (Good band).
Hawaii County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 201 monitored days across EPA AQI categories.
Good
163
81%
Moderate
38
19%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Hawaii County.
- PM2.5 · 201 days · 100.0%
Health Impact Assessment
Good
Hawaii County's air quality is rated Good based on 81.1% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 81.1% of monitored days in 2025, with a median AQI of 30. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 201 of 201 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Hawaii County. Best year: 2024 (355 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 352 | 14 | 0 | 0 | 23 | 83 |
| 2021 | 336 | 29 | 0 | 0 | 27 | 65 |
| 2022 | 328 | 37 | 0 | 0 | 33 | 71 |
| 2023 | 336 | 29 | 0 | 0 | 23 | 71 |
| 2024 | 355 | 11 | 0 | 0 | 21 | 75 |
| 2025 | 163 | 38 | 0 | 0 | 30 | 78 |
How does Hawaii County compare?
How Hawaii County compares
Good-day share better than US avg
Hawaii County 81.1%
Honolulu County, Hawaii 95.0%
US average 76.5%
Median AQI better than US avg
Hawaii County 30
Honolulu County, Hawaii 31
US average 38
Unhealthy days / yr about average
Hawaii County 0
Honolulu County, Hawaii 0
US average 0
Other Counties in Hawaii
Air quality comparison for nearby counties in Hawaii.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Hawaii County.
Canyon County, Idaho
AQI 30 · 87.2% good
Guaynabo County, Puerto Rico
AQI 30 · 86.0% good
Lynchburg City County, Virginia
AQI 30 · 84.2% good
Putnam County, Tennessee
AQI 30 · 88.6% good
Salem City County, Virginia
AQI 30 · 79.6% good
Whatcom County, Washington
AQI 30 · 96.6% good
What Hawaii County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 30 means for exposure. Health guidance
- See how Hawaii County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Hawaii County with its Hawaii neighbours before drawing a conclusion about the region. All of Hawaii
Based on 201 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Hawaii County, Hawaii? ▼
Hawaii County has a median Air Quality Index (AQI) of 30, rated "Good." 81.1% of monitored days (163 out of 201) had good air quality in 2025.
What is the main pollutant in Hawaii County? ▼
The primary pollutant in Hawaii County is Fine Particles (PM2.5), which was the main AQI driver on 201 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Hawaii County have? ▼
In 2025, Hawaii County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 78.
Is the air quality in Hawaii County getting better or worse? ▼
Air quality in Hawaii County is worsening based on 5-year trends (2020-2025). Best year: 2024 with 355 good days. Worst year: 2025 with 163 good days.
What does AQI 30 mean for health? ▼
Hawaii County's median AQI of 30 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Hawaii County compare to other counties in Hawaii? ▼
Hawaii County has 81.1% good air days. Nearby counties in Hawaii: Honolulu (95.0% good), Maui (96.1% good).
What is the 90th percentile AQI in Hawaii County? ▼
The 90th percentile AQI for Hawaii County is 58, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 78 (Moderate).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir 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.