Air Quality in Fresno, California — Live
Live readings from PurpleAir sensors across Fresno — with free alerts the moment the air turns.
AQI 22 from 4 PurpleAir sensors · Trending up · data from PurpleAir
As of , the air quality in Fresno, California is AQI 22 — Good and rising — with PM2.5 at 4.0 µg/m³, the median of 4 live PurpleAir sensors reading 18 to 26. 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 Fresno: weeds pollen is the strongest of the three at a low 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 Fresno and Clovis, Sanger, Madera, Selma. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Fresno
The sensors Canairy reads in Fresno agree right now — all 4 sit in the Good band, a 8-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.5 mi NNW | 21 | Good |
| 4.8 mi E | 23 | Good |
| 5.9 mi NNE | 26 | Good |
| 5.9 mi E | 18 | Good |
Fresno sits in one of the hardest airsheds in the country. The American Lung Association's 2025 State of the Air report ranked the Fresno-Hanford-Corcoran area third worst in the nation for year-round particle pollution, and the region shows up near the top of the ozone and short-term soot lists too. The air has genuinely improved in recent years, but on a bad winter or a smoky summer day it is still some of the dirtiest air most Americans will breathe.
What Canairy does for Fresno
A clear verdict
Not just a number — a plain-English call for Fresno: 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 Fresno or across the country, on one screen.
What the air in Fresno is doing next
| When | AQI | Expected air quality | Main pollutant |
|---|---|---|---|
| Today | 50 | Good | PM2.5 |
Forecast from EPA AirNow for the Fresno 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.
The Valley traps whatever gets put into it
Fresno sits on the floor of the San Joaquin Valley, a long bowl walled by the Sierra Nevada to the east and the Coast Ranges to the west. In winter the air near the ground turns cold and heavy and a temperature inversion clamps down like a lid, sometimes for weeks at a stretch. The same still, damp conditions produce the region's famous tule fog. Whatever pollution the Valley generates has nowhere to go, so it accumulates day after day until a storm finally scours it out.
That is why Fresno's worst particle pollution comes in the cold months, not the hot ones. Much of the wintertime soot here is ammonium nitrate, a particle that forms in the air itself, and fog actually speeds up how much of it forms. So the grey, socked-in days that feel calm and quiet are often the ones when the PM2.5 reading climbs highest.
Wildfire smoke on top of an already loaded airshed
When the Sierra burns, the smoke slides straight down into the Valley and settles. The Creek Fire in the fall of 2020, which grew into the largest single-source wildfire in California history and burned close to 380,000 acres above Fresno, is the clearest example. For weeks the smoke sat over the region, and the 24-hour PM2.5 average reached nearly 200 micrograms in Clovis, Fresno and Madera - five to six times the federal limit - and topped 300 in Clovis and Madera on the worst day.
What made that season so punishing was how little escape there was. The Valley's geography that traps winter soot traps summer and fall smoke just as effectively, so a fire in the mountains can hold the entire region under hazardous air at once. Wildfire seasons like 2020 are the reason a lot of Fresno families started paying close attention to a daily air number in the first place.
Everyday sources: farms, freeways, and winter fires
Most of Fresno's air problem isn't wildfire at all - it is the ordinary business of the Valley. This is one of the most productive farming regions on earth, and agriculture together with diesel equipment puts a steady load into the air. Heavy trucks are the single biggest piece: they account for roughly 70 percent of the nitrogen oxides that cook into ozone, and Highway 99 and Interstate 5 funnel thousands of big rigs through the Valley every day. In summer, strong sunlight turns those emissions into ground-level ozone, the pollutant behind Fresno's smog warnings.
In winter the culprit shifts to wood smoke. The Valley Air District runs its Check Before You Burn program from November 1 through the end of February, and under Rule 4901 it can restrict residential wood burning to registered devices or ban it outright on days when the air is forecast to be bad. Checking the burn status before lighting a fireplace is one of the few pollution controls that comes down to an individual household choice, and on a stagnant Fresno night it makes a real difference.
Fresno air quality FAQ
What is the air quality in Fresno right now?
As of September 5, 2026 at 5:09 AM PDT, the air quality in Fresno, California is AQI 22 — Good — with PM2.5 at 4.0 µg/m³, the median of 4 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why is there smoke in the air in Fresno today?
It depends on the season. From summer into fall it is usually wildfire smoke off the Sierra Nevada, which slides down into the Valley and settles instead of blowing through. In the cold months it is more often residential wood smoke held near the ground by a temperature inversion, which is why the Valley Air District runs its Check Before You Burn program from November 1 through February. Haze here can also be ordinary Valley pollution rather than smoke at all - so the live PM2.5 reading at the top of this page is a better guide than the look of the sky.
Why is Fresno's air worse in winter than in summer?
Fresno sits on the floor of the San Joaquin Valley, and in the cold months a temperature inversion and tule fog trap air near the ground for weeks at a time. Fine particle pollution, much of it ammonium nitrate formed in the air and boosted by fog, builds up with nowhere to escape. Summer brings a different problem - ground-level ozone from traffic and heat - but the highest particle readings usually come on still, grey winter days.
Is there smoke in Fresno today?
Check the live AQI number at the top of this page - it pulls continuously from PurpleAir sensors across Fresno and Clovis, so it updates faster than waiting for a haze to build up outside your window. From late summer into fall, a jump usually means Sierra wildfire smoke, like the 2020 Creek Fire, sliding down into the Valley and settling. In winter it's more often wood smoke and ammonium nitrate trapped near the ground by a temperature inversion. Either way, today's Fresno AQI reading is a better guide than the look of the sky.
Does wildfire smoke reach Fresno?
Yes, and the Valley's geography makes it worse. When the Sierra Nevada burns, smoke settles into the Valley bowl and lingers. During the 2020 Creek Fire, the largest single-source wildfire in California history, the 24-hour PM2.5 average in Fresno, Clovis and Madera reached five to six times the federal limit and stayed hazardous for weeks. This page tracks those spikes as they happen so you are not guessing from the color of the sky.
Is there an air quality warning for Fresno today?
The live reading at the top of this page is the fastest way to find out — faster than waiting on an official notice. When conditions turn hazardous, the San Joaquin Valley Air Pollution Control District issues an Air Quality Advisory and posts hourly numbers through its Real-Time Air Advisory Network. Canairy draws on that same class of sensor data and sends a free alert the moment your saved Fresno location crosses into unhealthy air, so you're not stuck refreshing a government page to know.
Is there a daily air quality forecast for Fresno?
The San Joaquin Valley Air Pollution Control District publishes a daily forecast for the region, and that same forecast is what its Check Before You Burn program uses from November 1 through February to decide whether wood burning is allowed. The live number at the top of this page tells you what the air is doing right now, straight from PurpleAir sensors across Fresno and Clovis. The Canairy app adds an hourly forecast for the next 24 hours and sends a free alert if your saved Fresno location is heading into unhealthy air. Longer term the pattern here is seasonal: the highest particle readings usually come on still, grey winter days, and late summer into fall is when Sierra smoke is most likely to settle into the Valley.
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 Fresno, 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
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Air quality near Fresno
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