Fontana Real-Time AQI Tracker
Get Alerts For Unhealthy AQI In Your Area
When air quality in your area reaches unhealthy levels, we'll send you a quick alert, along with expert tips on how to reduce your exposure.
What's Actually In Fontana Air Today?
What High AQI Means for Your Lungs in Fontana
How to Read AQI
The Air Quality Index (AQI) measures how polluted the air is and how it may affect your health.
0–50 (Good): Air quality is satisfactory.
51–100 (Moderate): Acceptable, but some pollutants may pose minor concerns.
101–150 (Unhealthy for Sensitive Groups)
151–200 (Unhealthy)
201–300 (Very Unhealthy)
301+ (Hazardous)
Moderate
Still okay for most, but if you have asthma or allergies, take it easy and avoid long outdoor workouts.
Shop MERV 11 filters→What's the Right Filter for Your AQI Level?
Check Today's Live Real Time Air Quality Index AQI Map in Fontana, CA Now
Fontana air can swing from clear to hazy in an afternoon, and the live map above shows where it stands now. Filterbuy has built air filters in the U.S. since 2013; below is how we read Fontana's air and what we'd change at home.
TL;DR
Filterbuy's live AQI map on this page shows Fontana's current air quality from EPA AirNow and South Coast AQMD monitors. 0–50 is Good; above 100, sensitive groups should ease off. Ground-level ozone causes most high readings on hot afternoons, while diesel soot and wildfire smoke drive the rest, plus dust on windy days. At AQI 100, Filterbuy's action line, switch the HVAC to MERV 13 and run a portable HEPA air cleaner in each occupied room.
Key Takeaways
Fontana's regulatory monitor, run by the South Coast AQMD, has operated on Arrow Highway since 1981.
In 2023, the Arrow Highway monitor recorded 74 days above the federal 8-hour ozone standard.
San Bernardino County is the nation's most ozone-polluted county (State of the Air 2026).
Ozone breaks down indoors, but PM2.5, the fine particles in smoke and soot, lingers, so MERV 13 targets the particles.
In 2023, annual NO2 at the I-10 near-road monitor ran about 48% higher than at Arrow Highway.
Reading the Fontana AQI Map Before You Head Out
Check the color, then the pollutant. Filterbuy's Fontana AQI map above converts monitor data to the EPA's 0–500 index and names the pollutant behind the number. An ozone reading means moving exercise to the morning, while a PM2.5 reading means closing up and filtering. Our guide to how the AQI is calculated explains why a single pollutant sets the score.
What Fontana's AQI Colors Ask You to Do
Find the row that matches the current air quality in Fontana. AQI 100 is Filterbuy's action line. It sits at the top of the EPA's Moderate range. At 100 or higher, we tell customers to put MERV 13 in the HVAC, set the thermostat fan to On, run a portable HEPA air cleaner in each occupied room (bedrooms first) and close the house up.
FONTANA AQI CATEGORIES AND WHAT TO DO
Categories per EPA AirNow guidance.
Why the Fontana Number Can Miss What You See
NowCast averaging. AirNow weights recent hours, so fast-moving smoke shows up late.
One station, one address. The Arrow Highway site has measured ozone since 1981 but added continuous PM2.5 only in May 2023, so neighborhoods near Jurupa Hills can differ.
Ash is too big to count. The South Coast AQMD warns that windblown ash may escape its instruments, so the map can read green while ash falls. If you see or smell ash, close up and run the HVAC fan.
For street-level readings, see our guide to air quality by ZIP code.
Is Fontana's Air Safe to Breathe Right Now?
Fontana's air is safe for everyone when the live map reads 0 to 50, and at 51 to 100, only unusually sensitive people may notice symptoms. Above 100, AirNow guidance tells people with asthma or heart disease, children, older adults and outdoor workers to shorten hard exertion; above 150, it tells everyone to. Anyone with a heart or lung condition should follow a doctor's advice. See our air quality index guide and AQI levels for sensitive groups.
Where Fontana Gets Its Air Forecast and Alerts
The South Coast Air Quality Management District (South Coast AQMD) forecasts Fontana as part of its Central San Bernardino Valley area. Read today's and tomorrow's outlook on the South Coast AQMD forecast page, where the daily summary lists the cleanest time of day for an outdoor run. Our guide explains how to read an air quality forecast, and the Air Alerts email sign-up adds smoke, dust and no-burn advisories.
How Air Quality Changes from North Fontana to South Fontana
In Fontana, freight drives most block-by-block differences. I-10 cuts through the middle of the city, I-15 runs along its west edge and SR-210 crosses the north, with warehouses between them drawing steady diesel trucks. South Fontana carries the heaviest share, while north Fontana borders fire-prone foothills.
In 2022, a settlement with the California Attorney General over the Slover and Oleander warehouse beside a high school led Fontana to adopt what the state called its strictest warehouse ordinance, and the developer funded a five-year supply of air filters for up to 1,750 nearby households. The South Coast AQMD's Rule 2305 also makes large warehouses cut truck emissions or pay a fee. The old Kaiser Steel mill site (1942–1983), later a speedway, is slated for logistics. Compare nearby conditions on our Riverside AQI map, Los Angeles AQI map or the statewide California AQI map.
What Pushes Fontana's AQI Up
Ground-level ozone forms when vehicle and industrial emissions react in heat and sunlight. Sea breezes carry Los Angeles basin emissions inland, where the San Gabriel and San Bernardino mountains trap them, so hot, still afternoons bring the worst ozone.
Fine particulate (PM2.5) is soot and haze 2.5 micrometers or smaller, from diesel, smoke and reactions in the air. PM2.5 reaches deep into the lungs, while coarser PM10 dust rises on windy days.
When Filterbuy pulled the South Coast AQMD's 2023 data for Arrow Highway, ozone was the expected headline. The surprise: the annual fine-particle average sat above the federal level, yet no single day crossed the 24-hour limit. Alerts catch spikes, so that steady load falls to your HVAC filter.
WHAT FONTANA-AREA MONITORS RECORDED IN 2023
Source: Filterbuy analysis of South Coast AQMD 2023 data, Arrow Highway and I-10 near-road stations. Fireworks days excluded.
Filterbuy's ranking of cities with the worst air quality puts the Riverside–San Bernardino metro first.
When Wildfire Smoke Settles over Fontana
Mountain and hillside fires can push smoke over Fontana. On June 30, 2024, the South Coast AQMD issued a smoke advisory for Fontana as the Sierra Fire burned near Sierra Avenue. Our guide to wildfire smoke and the AQI explains why readings jump. Track plumes on the AirNow Fire and Smoke Map, and find smoke-day steps on our San Bernardino wildfire and smoke map and California wildfire and smoke map.
What a South Coast AQMD Advisory Means for Your Day
The South Coast AQMD issues advisories for smoke, windblown dust and ash, and no-burn days. A typical Fontana year runs like this:
Early July: Fireworks drove Fontana's only 2023 state sulfate exceedance (July 5).
Windy days: Keep windows shut against dust and ash, with the HVAC fan running.
November 1 through February: No-burn alerts cover fireplaces.
Any smoke day: Switch off swamp coolers and whole-house fans, since both pull outdoor air in.
No Ductwork or a Swamp Cooler? Options for Fontana Homes
Some Fontana homes cool with evaporative coolers, window units or mini splits with no filter slot. In those homes, portable HEPA air cleaners are the primary defense; see how HEPA and MERV filters compare.
Size it by smoke CADR (clean air delivery rate). The EPA Guide to Air Cleaners in the Home advises at least two-thirds of the room's square footage, so a 300 sq ft bedroom needs a smoke CADR of about 200.
Pick one from CARB's certified air cleaner list.
Skip ionizers and ozone generators. EPA advises against any air cleaner that produces ozone.
Fontana's Smog Is a Gas, Its Soot Is Not
On bad-air days, the question Filterbuy hears most is whether a better filter will help. Check AirNow and South Coast AQMD guidance first. Then, at AQI 100 or higher, take four steps whatever pollutant the map names:
MERV 13 in the HVAC. This whole-home layer moves far more air than any portable unit.
Thermostat fan to On. Auto filters only while heating or cooling; On filters all day.
A portable HEPA air cleaner in each occupied room. Bedrooms first; each unit treats its room harder than the central system can.
The house closed up. Keep windows and doors shut, and skip candles, frying, smoking and vacuuming without a sealed unit.
The pollutant name still matters: a pleated filter captures particles but not ground-level ozone, a gas, so on ozone days, also exercise early.
During a smoke event, check the filter often. EPA's smoke guidance says to replace it once it looks dark brown or black, which can be well before the normal interval. Filters that come back to us after a smoke week are visibly darker than after a clean month, so keep a spare MERV 13 on hand before fire season.
"The falling line is the part people misread. They see unhealthy days drop by two-thirds and assume the problem closed. What the data actually shows is a floor that keeps dropping and a ceiling that keeps spiking. The spike is the week your filter has to already be in the wall."
Michelle Wan, Brand Manager and Air Quality Writer, Filterbuy
Which Filter Fits Fontana's AQI Levels
MERV 13 is the tier Filterbuy recommends for smoke. We make it in 1-, 2- and 4-inch depths, and since a deeper filter holds more pleated media, it loads more slowly in smoke.
CHOOSING A FILTER FOR FONTANA CONDITIONS
Confirm your filter size before you order.
For smoky periods, EPA's smoke guidance recommends a MERV 13 or higher filter in the central system. It also notes that most furnaces and HVAC systems can use MERV 13 without equipment problems when the filter is replaced often. Our best MERV filter for wildfire smoke guide covers the upgrade. Measure with our air filter sizes guide, choose from Filterbuy's 600+ standard sizes or custom air filters, and set up filter auto-delivery so spares arrive before the next advisory.
Supporting Statistics
1. #1 in the U.S. for ozone.
San Bernardino County, State of the Air 2026.
Failed all three pollution measures.
Fontana tip: time outdoor plans around ozone.
Source: American Lung Association
2. 16 million sq ft of warehouses in 5 years.
Approved in south Fontana alone.
Fontana tip: MERV 13 near truck routes.
Source: California Attorney General
3. 90% of our time is spent indoors.
Some pollutants run 2 to 5 times higher inside.
Source: U.S. EPA
Frequently Asked Questions
What is the air quality in Fontana today?
Check Filterbuy's live Fontana AQI map at the top of this page. It shows the current AQI and the pollutant driving it.
Is the air quality bad in Fontana today?
Compare the live reading to the EPA's AQI scale. Above 100, sensitive groups should cut outdoor exertion; above 150, everyone should.
What is Fontana's PM2.5 level today?
Filterbuy's live map shows the current reading; Fontana's Arrow Highway monitor has measured PM2.5 continuously since May 2023.
Why is Fontana's air quality worse in summer?
Heat and sunlight turn emissions into ozone, and sea breezes push it inland until the mountains near Fontana trap it.
Does an air filter help on a bad air day in Fontana?
For particles, yes. MERV 13 is the tier Filterbuy recommends for smoke and diesel soot. Ozone is a gas a pleated filter doesn't capture, so timing helps more on ozone days.
Glossary
AQI (Air Quality Index): The EPA's 0–500 outdoor air scale, in six color-coded categories.
NowCast: The EPA method weighting recent hours most in current AQI readings.
PM2.5: Fine particulate matter 2.5 micrometers or smaller, found in smoke and vehicle exhaust.
Ground-level ozone: A lung-irritating gas formed when sunlight reacts with vehicle and industrial emissions.
South Coast AQMD: The regional agency that monitors and regulates Fontana's air.
MERV: Minimum Efficiency Reporting Value, the 1–16 scale for HVAC filter capture.
CARB: The California Air Resources Board, which certifies air cleaners.