Air Quality in Fontana, California — Live
Live readings from PurpleAir sensors across Fontana — with free alerts the moment the air turns.
AQI 24 from 3 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Fontana, California is AQI 24 — Good and holding steady — with PM2.5 at 4.3 µg/m³, the median of 3 live PurpleAir sensors reading 20 to 28. 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 Fontana: weeds pollen is the strongest of the three at a moderate 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 Fontana and Rialto, Rancho Cucamonga, Bloomington, Colton. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Fontana
The sensors Canairy reads in Fontana agree right now — all 3 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 |
|---|---|---|
| 3.3 mi W | 20 | Good |
| 3.3 mi W | 28 | Good |
| 3.3 mi W | 24 | Good |
Fontana was built around a steel mill. Henry J. Kaiser put it up in 1942 to feed his wartime shipyards, it was the largest integrated steelmaking plant on the West Coast, and it ran until December 1983. What replaced it was freight. Fontana now sits where Interstate 10, Interstate 15 and the 210 cross, and warehouses are concentrated heavily along the Slover Avenue corridor at the south end of town. That matters for the air in a specific, measurable way: heavy-duty diesel trucks are the main reason warehouse neighborhoods read higher for fine particles than the ZIP codes around them.
What Canairy does for Fontana
A clear verdict
Not just a number — a plain-English call for Fontana: 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 Fontana or across the country, on one screen.
What the air in Fontana is doing next
| When | AQI | Expected air quality | Main pollutant |
|---|---|---|---|
| Today | 97 | Moderate | ozone |
Forecast from EPA AirNow for the C San Bernardino 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.
South Fontana sued over a warehouse, and won
In 2021 the California Attorney General sued the City of Fontana over its approval of the Slover and Oleander project, a 205,000-square-foot warehouse in south Fontana bordering Jurupa Hills High School. The settlement announced in April 2022 described the area as carrying some of the highest pollution levels in all of California, and said warehouse development in the city had gone unchecked for five years.
The outcome was Fontana's Industrial Commerce Center Sustainability Standards Ordinance, which the Attorney General's office called the most stringent warehouse standards in the state. New industrial projects have to route truck traffic away from schools, hospitals and daycares, install solar covering all of a larger building's energy needs, use zero-emission forklifts and yard trucks on site, and put in landscaped buffers. The developer also funded landscaping at Jurupa Hills High School and a five-year supply of air filters for roughly 1,750 nearby households. It applies to future projects, not to the warehouses already standing.
What the research says about living near warehouses
This is not a vague worry. A NASA-funded study published in the journal GeoHealth in October 2024 looked at about 11,000 warehouses across Los Angeles, Riverside, San Bernardino and Orange counties — a region that handles 40 percent of all US cargo containers — and found that ZIP codes in the top quartile for warehouse floor space carried 0.16 micrograms per cubic meter more PM2.5, with top-quartile truck parking adding 0.21. During peak holiday shipping the gap widened to roughly 4 micrograms. A companion national study of 150,000 warehouses found nitrogen dioxide running about 20 percent higher near warehouse sites.
Regulators have responded on two tracks. California's siting guidance advises against putting housing within 1,000 feet of an industrial warehouse because of truck traffic, and the regional air district's warehouse rule requires buildings of 100,000 square feet or more to earn credit for emission-reducing actions — cleaner trucks, on-site charging, air filtration — or pay a mitigation fee. Neither of those makes the air on Slover Avenue the same as the air up in Sierra Lakes, which is the practical reason to watch a sensor near your own address rather than a citywide number.
The mill is still there, and so is the ozone
Part of the original Kaiser plant still runs as California Steel Industries, and Auto Club Speedway went up on another piece of the site. Airborne emissions at the mill were already a public argument by 1970 — Fontana has been arguing about its own air for over half a century.
Layered on top of the local sources is the regional problem nobody here controls. Fontana sits at the downwind end of the basin, where the sea breeze deposits Los Angeles-area emissions after sunlight has cooked them into ozone. San Bernardino County ranked first in the nation for ozone in the American Lung Association's 2026 report, with 159.2 weighted unhealthy days a year.
Fontana air quality FAQ
What is the air quality in Fontana right now?
As of September 10, 2026 at 5:09 AM PDT, the air quality in Fontana, California is AQI 24 — Good — with PM2.5 at 4.3 µg/m³, the median of 3 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why is there smoke in Fontana today?
Fontana itself does not usually burn, but it sits downwind and downslope of country that does. The Cajon Pass is just northeast, and when the Blue Cut Fire burned roughly 37,000 acres there in August 2016 the smoke advisory named the northwest San Bernardino Valley. Fires in the San Bernardino National Forest, like the Line Fire near Highland in September 2024, put smoke into the same valley. Smoke can also arrive from the west. And in summer, a brown afternoon sky is often ozone rather than smoke.
Is it worse to live near the warehouses in south Fontana?
Measured air quality does differ near heavy warehouse and truck activity. Peer-reviewed work published in GeoHealth in 2024 found meaningfully higher PM2.5 in the Inland Empire ZIP codes with the most warehouse floor space and truck parking, and a national study found nitrogen dioxide about 20 percent higher near warehouses. The California Attorney General's 2022 settlement with the city specifically described south Fontana as carrying some of the highest pollution levels in California.
What did the Fontana warehouse ordinance actually change?
After the state sued over the Slover and Oleander project next to Jurupa Hills High School, Fontana adopted the Industrial Commerce Center Sustainability Standards Ordinance in April 2022. New industrial projects must keep truck routes away from schools, hospitals and daycares, put solar on larger buildings sufficient to cover their energy needs, use zero-emission forklifts and yard trucks, and install landscaped buffers. It governs future projects, not the warehouses already built.
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 3 curated PurpleAir sensors Canairy tracks in and around Fontana, 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 Fontana
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