Air Quality in Honolulu, Hawaii — Live
Live readings from PurpleAir sensors across Honolulu — with free alerts when vog drifts in from Kilauea.
AQI 1 from 4 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Honolulu, Hawaii is AQI 1 — Good and holding steady — with PM2.5 at 0.1 µg/m³, the median of 4 live PurpleAir sensors reading 0 to 1. Canairy's verdict: Breathe easy.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Honolulu: grass pollen is the strongest of the three at a none level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Honolulu and Pearl City, Kailua, Kaneohe, Waipahu. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Honolulu
The sensors Canairy reads in Honolulu agree right now — all 4 sit in the Good band, a 1-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 0.4 mi NNW | 1 | Good |
| 0.6 mi SSE | 1 | Good |
| 0.9 mi ENE | 1 | Good |
| 3.1 mi E | 0 | Good |
Honolulu has some of the cleanest air of any major U.S. city most of the year. The trade winds that blow steadily off the open Pacific keep pollution from building up, and the city's annual PM2.5 average — roughly 3.5 to 4 micrograms per cubic meter — sits well inside the World Health Organization's guideline. The real exception is vog: volcanic smog from Kilauea, more than 200 miles away on Hawaii Island, which can drift over Oahu when those trade winds weaken or reverse, mostly in winter.
What Canairy does for Honolulu
A clear verdict
Not just a number — a plain-English call for Honolulu: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Honolulu or across the country, on one screen.
What the air in Honolulu is doing next
| When | Expected air quality | Main pollutant |
|---|---|---|
| Today | Good | ozone |
Forecast from EPA AirNow for the Honolulu reporting area. Canairy watches the live sensors against it and tells you when the air actually crosses your threshold, rather than leaving you to check.
Honolulu's air is about as clean as it gets
Government monitoring and independent tracking from IQAir both put Honolulu's annual average PM2.5 at roughly 3.5 to 4 micrograms per cubic meter in recent years — under the World Health Organization's annual guideline of 5, and cleaner than almost any major mainland city. Most of that comes down to geography: Oahu sits in the open Pacific with nothing upwind for thousands of miles, and the northeast trade winds that blow on most days constantly flush the island's air out to sea.
That steady wind is also why Honolulu rarely deals with the kind of local pollution that piles up in valley or basin cities — there's no ridgeline here to hold smoke or exhaust in place overnight. The tradeoff is that when the trade winds do weaken or reverse, a shift locals call Kona weather, whatever is in the air has nowhere to go and can hang around longer than usual.
The real story here is vog, drifting over from Kilauea
Oahu has no active volcanoes of its own, but it sits downwind of one of the most active volcanoes on Earth. Kilauea, on Hawaii Island roughly 200 miles southeast, has erupted repeatedly since December 2020, with further episodes in 2021, 2022, 2023, and 2024. Each eruption releases sulfur dioxide that reacts with sunlight, moisture, and oxygen to form the fine sulfate particles known as vog. The City and County of Honolulu's 2025 hazard mitigation plan specifically calls out the September 2023 eruption, which released an estimated 209,000 tons of sulfur dioxide a day, as a vog-producing event felt beyond Hawaii Island.
Under normal conditions, the northeast trade winds push that plume toward the Kona side of Hawaii Island and out over open ocean, sparing Oahu almost entirely. It's when those trade winds go quiet — most often in winter — that vog can spread across the whole state, including Honolulu. By the time it reaches Oahu it has mostly converted to fine PM2.5 rather than raw sulfur dioxide gas, so the city's own hazard plan rates the health impact here as minor for most residents, occasionally reaching levels that matter for people with asthma, heart conditions, or other sensitivities.
How the state tracks it, and what the color codes mean
The Hawaii Department of Health runs stationary air monitors on Oahu at Honolulu, Kapolei, and Sand Island, tracking PM2.5, PM10, and sulfur dioxide, while the USGS Hawaiian Volcano Observatory tracks Kilauea's gas emissions to help forecast vog days before it arrives. The state uses a color-coded sulfur dioxide advisory scale — green, yellow, orange, red, purple, and maroon — running from 'good' to 'hazardous,' with sensitive groups advised to take precautions well before conditions affect the general population.
Those three official stations cover a lot of ground for one island, though, which is where a denser network helps. Canairy reads PurpleAir sensors scattered across Honolulu's neighborhoods, from downtown to the east side, so you can see how the air near your own house compares to the citywide picture instead of relying on whichever official monitor happens to be closest.
Honolulu air quality FAQ
What is the air quality in Honolulu right now?
As of September 14, 2026 at 5:10 AM PDT, the air quality in Honolulu, Hawaii is AQI 1 — Good — with PM2.5 at 0.1 µg/m³, the median of 4 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Honolulu sometimes get hazy — is that vog?
Usually, yes. Vog is volcanic smog that drifts over from Kilauea on Hawaii Island, more than 200 miles away. Trade winds normally carry it out to sea before it reaches Oahu, but when those winds weaken or reverse — most often in winter — vog can settle over Honolulu as a fine haze. On Oahu it shows up mostly as elevated PM2.5 rather than the stronger sulfur dioxide levels found closer to the volcano.
Is Honolulu's air quality usually good?
Yes. Honolulu's annual average PM2.5 typically runs around 3.5 to 4 micrograms per cubic meter, well inside the World Health Organization's guideline, thanks to steady trade winds off the open Pacific. The main exception is vog from Kilauea, which can raise particle levels for a few days at a time, mostly in winter when the trade winds falter.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 4 curated PurpleAir sensors Canairy tracks in and around Honolulu, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
Go deeper
Air quality near Honolulu
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