Air quality in Hawaii County, HI

Q: How often is the air bad in Hawaii County?

From 2021 to 2025, monitors in Hawaii County recorded almost no bad-air days a year with an AQI above 100, which is unhealthy for sensitive groups or worse. No year from 2021 to 2025 had a bad-air day.

Q: Where can I see today's air quality in Hawaii County?

AirNow, run by the EPA and its partners, shows the current AQI and tomorrow's forecast for your ZIP code. Its fire and smoke map adds smoke plumes. On a typical day the AQI in Hawaii County is about 27, which is good, fine for everyone. Check it most in March, May and June, when bad days here cluster.

Includes Hilo and Kailua · EPA monitor readings, 2021 to 2025 (fine particles only) · 200,000 people

Clean most daysOnly particles are measured

For today's air and tomorrow's forecast, check AirNow by ZIP code.

Bad-air days a year

day with an AQI over 100

No bad-air days from 2021 to 2025. Hawaii County has the fewest bad-air days of the 3 Hawaii counties with monitors.

0days unhealthy for everyoneAQI over 150, a year

27AQI on a typical dayGood: fine for everyone

Mar, May and Junworst monthsFine particles, the only pollutant measured

153worst day since 2016May 29, 2018, fine particles

How to read the AQIThe EPA's air score runs from 0 to 500. Higher is worse. Over 100 counts as a bad-air day.

Typical day 27 (Good)Worst day 153 (Unhealthy)

Good0 to 50Moderate51 to 100Sensitive groups101 to 150Unhealthy151 to 200Very unhealthy201 to 300Hazardous301 to 500

When bad air happens in Hawaii County

Average bad-air days in each month, from 10 years of daily readings since 2016. Most fall in March, May and June. Only fine particles are measured here.

Jan0

Feb0.1

Mar0.3

Apr0.1

May0.5

Jun0.6

Jul0.2

Aug0

Sep0

Oct0

Nov0

Dec0.1

Fine particles (smoke, soot)Ozone (smog)Bars stack in that order, from the bottom.

See the numbers by month

Average bad-air days a year in each month in Hawaii County, from 10 years of daily readings
Month	Fine particles	All
January	0	0
February	0.1	0.1
March	0.3	0.3
April	0.1	0.1
May	0.5	0.5
June	0.6	0.6
July	0.2	0.2
August	0	0
September	0	0
October	0	0
November	0	0
December	0.1	0.1

The worst day since 2016 was May 29, 2018: AQI 153, from fine particles.

What causes it

Fine particles are the only pollutant measured here. Most bad days counted here are fine-particle days, spread through the year, with the most in March, May and June. Monitors here don't measure ozone, so smog days aren't in these counts.

What helps in Hawaii County

Monitors here track fine particles such as smoke, so filtering the air at home helps most. Check the forecast for ozone, which isn't measured here.

Keep one room clean on smoky days

Shut the windows and run an air purifier sized for the room.

Choosing a purifier →

Upgrade the furnace filter

Use MERV 13 if your system can take it, and run the fan on smoky days.

Furnace filters →

Check tomorrow's forecast

AirNow posts an air quality forecast by ZIP code, usually the day before.

AirNow →

For today's reading and tomorrow's forecast, check AirNow by ZIP code. Its fire and smoke map adds smoke plumes.

Purifiers with a verified smoke rating

For a clean room on smoky days. Each has a smoke CADR tested by AHAM's independent program and is certified by California as a mechanical cleaner, so it makes no ozone.

Bedroom or small room

Levoit Vital 100S-P

143 smoke CADR

Everyday: up to 222 sq ft
Heavy smoke: up to 143 sq ft
Filters: about $40 a year

The cheapest unit we found with a verified smoke rating. Enough for a bedroom clean room.

$119.99 at Levoit

Best value for smoke

Levoit Vital 200S-P

250 smoke CADR

Everyday: up to 388 sq ft
Heavy smoke: up to 250 sq ft
Filters: about $50 a year

The most verified smoke cleaning per dollar of any qualifying model: 75% more than the 100S-P for $50 more.

$169.99 at Levoit

Living room or open floor

Levoit Core 600S-P

391 smoke CADR

Everyday: up to 606 sq ft
Heavy smoke: up to 391 sq ft
Filters: $60 to $120 a year

For a big room or a small apartment. Buy the LAP-C601S-WUS version, which CARB lists as mechanical.

$299.99 at Levoit

Why all 3 are Levoit: of the models we checked that pass both tests, these give the most verified smoke cleaning per dollar at each room size. Medify's MA-25 and MA-40 also pass but cost more for the same cleaning.

Ratings from the AHAM Verifide directory and CARB's certified list. Prices from Levoit's site, checked November 7, 2026; they change. We don't earn anything from these links. How to pick a purifier

Every year since 2000

Bad-air days each year. The striped part is days unhealthy for everyone, over AQI 150. No year from 2021 to 2025 had a bad-air day.

Unhealthy for sensitive groups (101 to 150)Unhealthy or worse (over 150)

See the numbers by year

Bad-air days each year in Hawaii County
Year	Bad-air days	Over 150
2000	0	0
2001	0	0
2002	0	0
2003	0	0
2008	31	7
2009	24	4
2010	15	2
2011	0	0
2012	2	2
2013	0	0
2014	2	0
2015	0	0
2016	5	0
2017	0	0
2018	14	2
2019	0	0
2020	0	0
2021	0	0
2022	0	0
2023	0	0
2024	0	0
2025	0	0

Hawaii County and its neighbors

Bad-air days a year, 2021 to 2025. Hawaii counties with monitors averaged almost no bad-air days a year, weighted by population.

Hawaii County<1

Questions people ask about air in Hawaii County

How often is the air bad in Hawaii County?

From 2021 to 2025, monitors in Hawaii County recorded almost no bad-air days a year with an AQI above 100, which is unhealthy for sensitive groups or worse. No year from 2021 to 2025 had a bad-air day.

What causes bad air in Hawaii County?

Most bad days counted here are fine-particle days, spread through the year, with the most in March, May and June. Monitors here don't measure ozone, so smog days aren't in these counts.

Where can I see today's air quality in Hawaii County?

AirNow, run by the EPA and its partners, shows the current AQI and tomorrow's forecast for your ZIP code. Its fire and smoke map adds smoke plumes. On a typical day the AQI in Hawaii County is about 27, which is good, fine for everyone. Check it most in March, May and June, when bad days here cluster.

About these numbers

Day counts come from the EPA's county air quality summaries, which take the worst reading across a county's monitors each day. Monitors here reported on about 365 days a year from 2021 to 2025. A county is large, and your street can be cleaner or worse. CDC's modeled estimates, used on our map, don't cover Alaska or Hawaii, so the monitor numbers above are the whole picture here.

Sources: EPA AirData county AQI summaries (2000 to 2025) and daily county AQI (2016 to 2025); CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone (2001 to 2022). Updated November 8, 2026.