Air Quality in Corona, California — Live
Live readings from PurpleAir sensors across Corona — with free alerts the moment the air turns.
AQI 12 from 5 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Corona, California is AQI 12 — Good and holding steady — with PM2.5 at 2.1 µg/m³, the median of 5 live PurpleAir sensors reading 11 to 50. 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 Corona: 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 Corona and Norco, Eastvale, Yorba Linda, Temescal Valley. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Corona
The sensors Canairy reads in Corona agree right now — all 5 sit in the Good band, a 39-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 2.2 mi WSW | 11 | Good |
| 5.7 mi SSE | 12 | Good |
| 6.6 mi WNW | 50 | Good |
| 7.7 mi SSE | 13 | Good |
| 8.8 mi NW | 18 | Good |
Corona sits at the east end of the Santa Ana Canyon, on the northeastern edge of the Santa Ana Mountains, about 45 miles southeast of Los Angeles. The canyon is the water gap where the Santa Ana River cuts between the Santa Ana Mountains and the Chino Hills, and it is the low doorway between coastal Orange County and inland Riverside County. Almost everything that moves between the two goes through it, including the 91 freeway. More than 280,000 vehicles a day use the 91 at the Orange and Riverside county line, and in the Southern California Association of Governments' 2024 congestion report the westbound 91 at Green River Road in Corona is the worst bottleneck in Riverside County and the seventh worst of any in the six-county region, with roughly 1.19 million hours of vehicle delay a year spread over 4.3 miles.
What Canairy does for Corona
A clear verdict
Not just a number — a plain-English call for Corona: 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 Corona or across the country, on one screen.
One freeway, one canyon, and everything squeezed through both
Corona's traffic problem and its air problem are the same shape. The Santa Ana Canyon is narrow, and the 91 is the only continuous freeway through it, which is why a corridor that carries more than 280,000 vehicles a day collapses to a crawl twice a day at the county line. The SCAG analysis puts the westbound queue at Green River Road at 4.3 miles long and about 1.19 million annual hours of vehicle delay. Idling and stop-start driving are the worst possible way to burn fuel, and the pollution from it lands on the neighbourhoods immediately either side of the freeway rather than dispersing.
SCAG makes the connection itself in that report, noting that many of the region's bottlenecks sit next to communities already carrying a higher pollution burden, with higher rates of asthma. If you live in south Corona up against the hills, a mile or two from the freeway, your air can be meaningfully different from a house in Green River or along the Auto Center Drive corridor on the same afternoon. That is the case for reading a sensor near you rather than a citywide number.
The winds are named after the canyon next door
The Santa Ana winds take their name from Santa Ana Canyon, where they blow hardest, and the earliest documented use of the phrase is an 1871 item in the Anaheim Gazette. They are katabatic winds, meaning they flow downhill, driven by high pressure over the Great Basin and the upper Mojave. As the air descends it warms by roughly 5 degrees Fahrenheit per thousand feet and its relative humidity collapses, often below 10 percent. Speeds regularly exceed 40 miles an hour.
For air quality this cuts both ways. A Santa Ana event scours the basin's smog out toward the ocean, so the sky can look startlingly clear. But the same wind lifts dust off bare ground and carries smoke a long way in a hurry, and it is what turns a roadside spark into a disaster. Corona knows what that looks like. On the morning of 15 November 2008, hot debris from a vehicle's catalytic converter started a fire beside the 91 in Corona. It merged with a second fire at the Olinda landfill and became the Freeway Complex Fire, which burned 30,305 acres across Orange and Riverside counties, destroyed 314 homes along with 43 outbuildings and four commercial buildings, forced roughly 40,000 people out of their houses, and closed the 91, the 71, the 57 and the 241.
Corona air quality FAQ
What is the air quality in Corona right now?
As of September 10, 2026 at 5:10 AM PDT, the air quality in Corona, California is AQI 12 — Good — with PM2.5 at 2.1 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why is there smoke in Corona today?
Check the wind first. If it is a hot, dry, windy day with the wind coming from the north or east, a fire anywhere in the Chino Hills or the Santa Ana Mountains can put smoke over Corona within an hour, because Santa Ana winds regularly exceed 40 miles an hour and carry smoke a long way fast. The Freeway Complex Fire in November 2008 started beside the 91 here on exactly that kind of day and burned 30,305 acres. If instead the air is hazy and still on a hot summer afternoon with no wind and no smell of smoke, it is more likely to be the regional smog layer working its way inland rather than a fire.
Is it worse to live near the 91?
The 91 through Corona carries more than 280,000 vehicles a day at the county line, and the westbound approach to Green River Road is the worst traffic bottleneck in Riverside County by annual hours of delay. Vehicle pollution is concentrated close to the road and drops off sharply with distance, so a home a few hundred metres from the freeway is in a different situation from one a mile up into the hills. If you are near it, the practical steps are keeping windows on the freeway side shut during the morning and evening peaks and running a filter in the room where you sleep.
Do the Santa Ana winds clean the air or make it worse?
Both, at different times. A strong Santa Ana pushes the basin's accumulated smog out toward the coast, which is why the mountains look unusually sharp on those days. But the same wind picks up dust from bare ground and construction sites, and it is the reason Southern California's most destructive fires happen in autumn rather than midsummer. The useful habit is not to assume a windy day is a clean day. Look at the actual reading.
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 5 curated PurpleAir sensors Canairy tracks in and around Corona, 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 Corona
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