EnviroNearby

Honolulu County, Hawaii air quality history

Daily Air Quality Index summaries from EPA monitors in Honolulu, Hawaii, 1980–2025.

97%
Good days in 2025
29
Median daily AQI, 2025
0
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Honolulu, Hawaii on 365 days. 355 of those days (97%) were in the Good range, and the median daily AQI was 29. That median is about the same as 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 ozone on 226 days. Across the years with fuller monitoring, the share of Good days rose: an average of 92% in 1980–1982 versus 96% in 2023–2025.

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.

Share of monitored days in each AQI category, by year0%25%50%75%100%1980: Good 366 of 366 days19801981: Good 324 of 361 days1981: Moderate 37 of 361 days1982: Good 320 of 365 days1982: Moderate 44 of 365 days1982: Unhealthy for Sensitive Groups 1 of 365 days1983: Good 338 of 365 days1983: Moderate 27 of 365 days1984: Good 336 of 365 days1984: Moderate 28 of 365 days1984: Unhealthy 1 of 365 days1985: Good 345 of 365 days1985: Moderate 20 of 365 days19851986: Good 361 of 365 days1986: Moderate 4 of 365 days1987: Good 365 of 365 days1988: Good 366 of 366 days1989: Good 365 of 365 days1990: Good 364 of 365 days1990: Moderate 1 of 365 days19901991: Good 363 of 365 days1991: Moderate 2 of 365 days1992: Good 361 of 366 days1992: Moderate 4 of 366 days1992: Unhealthy for Sensitive Groups 1 of 366 days1993: Good 362 of 365 days1993: Moderate 3 of 365 days1994: Good 359 of 365 days1994: Moderate 6 of 365 days1995: Good 363 of 365 days1995: Moderate 2 of 365 days19951996: Good 366 of 366 days1997: Good 365 of 365 days1998: Good 364 of 365 days1998: Moderate 1 of 365 days1999: Good 334 of 365 days1999: Moderate 29 of 365 days1999: Unhealthy 2 of 365 days2000: Good 337 of 366 days2000: Moderate 27 of 366 days2000: Unhealthy 1 of 366 days2000: Very Unhealthy 1 of 366 days20002001: Good 337 of 365 days2001: Moderate 26 of 365 days2001: Unhealthy 1 of 365 days2001: Very Unhealthy 1 of 365 days2002: Good 355 of 365 days2002: Moderate 8 of 365 days2002: Unhealthy for Sensitive Groups 1 of 365 days2002: Unhealthy 1 of 365 days2003: Good 346 of 365 days2003: Moderate 17 of 365 days2003: Unhealthy for Sensitive Groups 1 of 365 days2003: Unhealthy 1 of 365 days2004: Good 357 of 366 days2004: Moderate 7 of 366 days2004: Unhealthy 2 of 366 days2005: Good 343 of 365 days2005: Moderate 19 of 365 days2005: Unhealthy for Sensitive Groups 2 of 365 days2005: Unhealthy 1 of 365 days20052006: Good 354 of 365 days2006: Moderate 10 of 365 days2006: Unhealthy for Sensitive Groups 1 of 365 days2007: Good 356 of 365 days2007: Moderate 9 of 365 days2008: Good 346 of 366 days2008: Moderate 20 of 366 days2009: Good 290 of 365 days2009: Moderate 74 of 365 days2009: Unhealthy 1 of 365 days2010: Good 190 of 365 days2010: Moderate 174 of 365 days2010: Unhealthy 1 of 365 days20102011: Good 206 of 365 days2011: Moderate 158 of 365 days2011: Unhealthy for Sensitive Groups 1 of 365 days2012: Good 260 of 366 days2012: Moderate 106 of 366 days2013: Good 294 of 365 days2013: Moderate 71 of 365 days2014: Good 325 of 359 days2014: Moderate 33 of 359 days2014: Unhealthy 1 of 359 days2015: Good 283 of 365 days2015: Moderate 82 of 365 days20152016: Good 330 of 366 days2016: Moderate 36 of 366 days2017: Good 340 of 365 days2017: Moderate 25 of 365 days2018: Good 353 of 365 days2018: Moderate 12 of 365 days2019: Good 360 of 365 days2019: Moderate 5 of 365 days2020: Good 363 of 366 days2020: Moderate 3 of 366 days20202021: Good 364 of 365 days2021: Moderate 1 of 365 days2022: Good 356 of 365 days2022: Moderate 9 of 365 days2023: Good 337 of 365 days2023: Moderate 27 of 365 days2023: Unhealthy for Sensitive Groups 1 of 365 days2024: Good 360 of 366 days2024: Moderate 6 of 366 days2025: Good 355 of 365 days2025: Moderate 10 of 365 days2025
  • 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 and 90th-percentile daily AQI, by year0501001980: 90th percentile AQI 281981: 90th percentile AQI 511982: 90th percentile AQI 531983: 90th percentile AQI 481984: 90th percentile AQI 481985: 90th percentile AQI 441986: 90th percentile AQI 351987: 90th percentile AQI 331988: 90th percentile AQI 301989: 90th percentile AQI 321990: 90th percentile AQI 311991: 90th percentile AQI 311992: 90th percentile AQI 331993: 90th percentile AQI 391994: 90th percentile AQI 401995: 90th percentile AQI 381996: 90th percentile AQI 311997: 90th percentile AQI 341998: 90th percentile AQI 361999: 90th percentile AQI 492000: 90th percentile AQI 462001: 90th percentile AQI 452002: 90th percentile AQI 382003: 90th percentile AQI 422004: 90th percentile AQI 392005: 90th percentile AQI 432006: 90th percentile AQI 362007: 90th percentile AQI 352008: 90th percentile AQI 392009: 90th percentile AQI 542010: 90th percentile AQI 592011: 90th percentile AQI 612012: 90th percentile AQI 562013: 90th percentile AQI 542014: 90th percentile AQI 492015: 90th percentile AQI 562016: 90th percentile AQI 492017: 90th percentile AQI 462018: 90th percentile AQI 432019: 90th percentile AQI 412020: 90th percentile AQI 382021: 90th percentile AQI 392022: 90th percentile AQI 402023: 90th percentile AQI 472024: 90th percentile AQI 412025: 90th percentile AQI 391980: Median AQI 181981: Median AQI 301982: Median AQI 301983: Median AQI 311984: Median AQI 301985: Median AQI 261986: Median AQI 241987: Median AQI 221988: Median AQI 191989: Median AQI 191990: Median AQI 161991: Median AQI 201992: Median AQI 241993: Median AQI 291994: Median AQI 291995: Median AQI 221996: Median AQI 201997: Median AQI 241998: Median AQI 241999: Median AQI 292000: Median AQI 262001: Median AQI 272002: Median AQI 272003: Median AQI 272004: Median AQI 252005: Median AQI 262006: Median AQI 212007: Median AQI 212008: Median AQI 242009: Median AQI 402010: Median AQI 492011: Median AQI 432012: Median AQI 412013: Median AQI 372014: Median AQI 322015: Median AQI 392016: Median AQI 322017: Median AQI 322018: Median AQI 312019: Median AQI 282020: Median AQI 282021: Median AQI 282022: Median AQI 292023: Median AQI 312024: Median AQI 312025: Median AQI 291980198519901995200020052010201520202025
  • 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.

PollutantDays as main pollutantShare of monitored days
Ozone22662%
Fine particles (PM2.5)13838%
Coarse particles (PM10)1<1%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025365355100000293959Ozone
202436636060000314185Ozone
20233653372710003147117PM2.5
202236535690000294057PM2.5
202136536410000283958Ozone
202036636330000283863Ozone
201936536050000284162Ozone
2018365353120000314373Ozone
2017365340250000324668Ozone
2016366330360000324964Ozone
2015365283820000395666PM2.5
20143593253301003249195PM2.5
2013365294710000375471PM2.5
20123662601060000415678PM2.5
201136520615810004361101PM2.5
201036519017401004959155PM2.5
20093652907401004054165PM2.5
2008366346200000243999Ozone
200736535690000213571Ozone
20063653541010002136149Ozone
20053653431921002643174PM2.5
2004366357702002539184PM2.5
20033653461711002742176PM2.5
2002365355811002738152Ozone
20013653372601102745220PM2.5
20003663372701102646206PM2.5
19993653342902002949186PM2.5
199836536410000243675Ozone
199736536500000243446Ozone
199636636600000203148Ozone
199536536320000223862Ozone
199436535960000294072Ozone
199336536230000293964Ozone
1992366361410002433105Ozone
199136536320000203157Ozone
199036536410000163153CO
198936536500000193244CO
198836636600000193048CO
198736536500000223345CO
198636536140000243556CO
1985365345200000264465CO
19843653362801003048165CO
1983365338270000314871CO
19823653204410003053115CO
1981361324370000305180CO
198036636600000182834Ozone

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 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem