Maui County, Hawaii air quality history

Daily Air Quality Index summaries from EPA monitors in Maui, Hawaii, 1987–2025.

98%

Good days in 2025

Median daily AQI, 2025

Days above 100 in 2025

360

Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Maui, Hawaii on 360 days. 353 of those days (98%) were in the Good range, and the median daily AQI was 21. That median is lower than the typical monitored county in Hawaii (median 29 across 3 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 360 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 100% in 1991–1993 versus 99% in 2023–2025.

Years with fewer than 120 monitored days (1987, 1988, 1989, 1990) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median daily AQI
90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

Pollutant	Days as main pollutant	Share of monitored days
Fine particles (PM2.5)	360	100%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2025	360	353	7	0	0	21	32	69	PM2.5
2024	364	363	0	1	0	21	33	101	PM2.5
2023	347	344	2	0	1	20	33	152	PM2.5
2022	361	357	4	0	0	21	34	58	PM2.5
2021	363	361	2	0	0	21	31	63	PM2.5
2020	349	343	6	0	0	21	31	61	PM2.5
2019	362	339	19	3	1	20	39	171	PM2.5
2018	361	347	14	0	0	25	39	76	PM2.5
2017	364	332	32	0	0	28	48	88	PM2.5
2016	366	324	41	1	0	28	51	130	PM2.5
2015	365	310	55	0	0	33	53	77	PM2.5
2014	341	305	35	1	0	29	51	136	PM2.5
2013	362	285	77	0	0	37	56	81	PM2.5
2012	349	302	47	0	0	33	52	68	PM2.5
2011	320	283	37	0	0	29	52	65	PM2.5
2010	343	322	21	0	0	24	46	78	PM2.5
2009	358	338	20	0	0	17	39	82	PM2.5
2008	346	331	15	0	0	19	38	63	PM10
2007	335	310	24	0	1	22	44	164	PM10
2006	346	338	8	0	0	20	34	89	PM10
2005	345	328	16	1	0	21	41	101	PM10
2004	324	319	5	0	0	18	32	56	PM10
2003	348	327	21	0	0	21	41	80	PM10
2002	353	345	8	0	0	20	34	69	PM10
2001	359	343	16	0	0	21	38	69	PM10
2000	358	346	12	0	0	23	42	64	PM10
1999	352	325	27	0	0	20	46	89	PM10
1998	346	315	31	0	0	25	47	88	PM10
1997	363	356	7	0	0	21	34	76	PM10
1996	243	241	2	0	0	15	27	57	PM10
1995	225	224	1	0	0	28	38	65	Ozone
1994	356	356	0	0	0	28	36	44	Ozone
1993	357	357	0	0	0	28	37	45	Ozone
1992	358	356	2	0	0	23	35	56	Ozone
1991	230	229	1	0	0	19	29	52	Ozone
1990	42	42	0	0	0	18	27	39	PM10
1989	40	40	0	0	0	22	34	47	PM10
1988	33	33	0	0	0	23	35	44	PM10
1987	18	18	0	0	0	27	34	39	PM10

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Hawaii with a similar median AQI in 2025

All monitored counties in Hawaii

Source: U.S. EPA AirData, “Annual AQI by County” files for 1987–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem