Irvine, CA Air Quality Index (AQI) Today

That reading is today’s call on Irvine air quality — color first, number right behind it. What it decides is smaller than the headline. The loop around the park. Whether soccer practice moves indoors. Whether tonight’s windows stay open. This page also tracks the air quality Irvine has breathed over the past month, not just the figure refreshing above. Skip refreshing it yourself. Pick your number and be told when the basin crosses it instead.

Irvine’s last 30 days, not just today

A single reading hides the shape behind it. This rebuilds the air quality Irvine saw over the trailing 30 days, off the same hourly AQI feed as the number above. It also carries a running count of days above AQI 100 in the last 12 months. IQAir, AccuWeather and the state’s own monitor grid stop at today’s figure; none show the metro’s shape over time. Irvine runs ozone-dominant, the same bracket as Los Angeles, Denver, Houston and Phoenix. Afternoon spikes come on hot, still days, not one long winter smear. A rough Tuesday that clears by Thursday still shows up here.

Why is it hazy in Irvine today?

Irvine sits inland of the Orange County coast — closer to the water than downtown Los Angeles, but still boxed in. The San Joaquin Hills sit to the southwest. The Santa Ana Mountains’ foothills sit to the northeast. The same marine layer that keeps the immediate coastline clear pushes inland and stalls against that high ground. Instead of protecting Irvine, it traps what the basin’s own traffic produces. Same basin, same mechanism as Los Angeles — opposite outcome, for a city that looks, on the map, like it should catch a coastal break. Los Angeles sits in the wider version of this basin. Long Beach adds the port complex’s own traffic to it. Both feed air that eventually reaches Irvine.

The sky can also look worse than the number. A 24-hour average smooths a bad afternoon across twenty calmer hours. Smoke from a basin fire can sit aloft, above the monitor. Or the nearest station just sits far enough away that it’s standing in for ground it isn’t actually over. A marine layer, an inland push, an averaged number works through each cause.

The peak lands in December, not fire season. Search volumes, not AQI readings — bars are neutral blue-grey with the peak month in accent blue, never EPA band colours, so demand data can never be read as a measurement of the air.

What is causing the bad air in Irvine?

Ground-level ozone is the mechanism that matters most here. It explains why a clear afternoon can still post a mediocre number. Sunlight cooks vehicle exhaust into ozone through the day, peaking on hot, still afternoons — often worse a few miles inland than right at the beach. Irvine sits between two of the region’s busiest corridors, I-5 and the 405. Their exhaust has all day to react before the hills stop it from draining out. The EPA AQI breakpoints track six pollutants in total — PM2.5, PM10, ozone, NO2, SO2 and CO — and ozone is the one that dominates an Irvine afternoon. Wildfire smoke reaches Irvine too, riding the same basin currents that carry it into Los Angeles and Long Beach. We don’t have an Irvine-specific fire event on file, so we’re not inventing one. What’s actually in that smoke covers the mechanics, including here.

Is the air safe to breathe in Irvine today?

Irvine sits close enough to the coast that a marine layer should clear the air the way it does right at the beach. Instead, the San Joaquin Hills and the Santa Ana foothills box that layer in, trapping the same basin traffic Los Angeles deals with, just from the inland side. Go on a clean reading. Short and unloaded: the short dog loop instead of the long one. Don’t go past the middle band. EPA’s everyone warning opens at 151, Unhealthy. 201 to 300, Very Unhealthy, is the same warning restated more seriously, not a different group. Past roughly 200, the coastal address doesn’t buy an exception.

What AQI should you stay inside?

Nothing California-specific turned up for a school or daycare AQI rule in the material reviewed here. Washington and Minnesota remain the two states with one documented. Where a daycare AQI rule is actually documented covers what’s confirmed.

Marine-layer haze and wildfire smoke shift personal thresholds by different amounts, and neither matches the EPA’s single sensitive-groups line to start with. An asthmatic runner logged 156 runs against AQI and set a ceiling of 60 — “my lungs struggle regardless of how well I’ve trained,” despite EPA calling nothing under 100 unhealthy. That log: 87% of runs under 50 went fine, 42% between 50 and 70, just 12% past 70. A runner on r/Marathon_Training runs nearly double that: “I’ll run in up to 110 because…error bars.” Parents this project has seen online land nearer 100.

Wildfire smoke, arriving on the same Santa Ana winds Los Angeles gets, pulls that whole table down about one EPA band. EPA’s name for that window is the Unhealthy for Sensitive Groups band, 101–150 — the agency’s, not this page’s judgment. Indoors, default to a portable HEPA purifier or a Corsi-Rosenthal box; one builder priced a 12x14 bedroom’s worth at $130. A whole-house MERV-13 swap needs a static-pressure check from a licensed tech first — it isn’t automatic in an inland system built for a marine-layer climate. What to buy indoors, and in which order covers it.

EPA AirNow’s own colours and breakpoints. The three marked cutoffs are not EPA guidance and not Irvine rules — each is one reader’s or one institution’s own line.

Why our number may not match what you are seeing and smelling

This runs both directions.

Direction one: the sky looks clear, the number is bad. Ground-level ozone, the dominant pollutant here, is invisible and odorless. A bright, still afternoon with no visible haze can still carry an AQI in the 100s. There’s no smelling your way to a safe read on it — only checking the number.

Direction two: the sky looks wrong, and the official line stays calm. It’s the same mechanics above, running in reverse — smoke sitting aloft, a distant station, a 24-hour average smoothing a rough hour.

That’s the monitoring station behind today’s reading — its distance from Irvine’s center, and the nearby PurpleAir sensor count. A station miles off under-reports whichever direction of the metro sits farthest from it. How much a station a few miles off changes the reading has the detail.

Search interest in air quality Irvine doesn’t come with its own named phenomenon, the way “brown cloud” names Denver’s or “smoke aloft” names Seattle’s. No local thread on file names one for Irvine specifically. That gap is stated here plainly, rather than filled with borrowed color. How Irvine ranks against every other tracked city today updates with the live number.

FAQ

What’s the air quality forecast for Irvine tomorrow?

Marine layer and wind direction can shift a forecast within hours here. Treat it as a direction, not a lock. Recheck the morning of.

What’s the UV index in Irvine today?

UV runs on its own scale, separate from AQI. A clear, low-AQI afternoon is often the highest-UV day of the week. A good air quality reading isn't a reason to skip sunscreen.

Who has the worst air quality in the US right now?

See how Irvine ranks today against every tracked city. Its own rank moves hardest during ozone season, and whenever basin-wide wildfire smoke is active.

What is in the air in Irvine right now?

That's today's specific reading. As a rule, ozone dominates hot, still afternoons here. PM2.5 from traffic, or from an active fire elsewhere in the basin, dominates the rest of the year.

Why does it smell like smoke outside in Irvine?

Wildfire smoke and an urban structure fire carry different particulate matter at the same AQI number. If a specific fire is active nearby, [Whether it's safe to go out under a plume](/wildfire-smoke/) covers the smoke case specifically.