Tucson, AZ Air Quality Index (AQI) Today

That reading and color are today’s Tucson call, nothing more. It decides the Sabino Canyon hike, the kid’s soccer practice, or whether the windows stay open tonight. This page tracks the air quality Tucson has actually breathed over the past 30 days, not just the number above. Set your own line and a text arrives when monsoon dust pushes past it.

Tucson’s last 30 days, not just today

Today’s number alone can’t separate an ordinary week from a dust event. This chart rebuilds the air quality Tucson has seen over the trailing 30 days, from 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, aqicn and Arizona’s own monitor grid show today’s number and stop there. A dust-storm day that clears by the next morning still shows up here instead of disappearing.

Tucson’s own search demand hints at why that history matters more here than in a smoke-driven metro. Averaged across the trailing year it runs 1,000 a month, against a typical month of 720. That’s a 1.4x gap between the average and the typical month. Madison, on the same average-to-typical measure, runs 13.8x, because one Canadian smoke month carries its whole year. Tucson’s dust is spread across the calendar instead, which is exactly the shape a single day’s number hides.

Why is it hazy in Tucson today?

Three things can make Tucson’s sky look worse than the number reads. The AQI is a 24-hour average, so one dusty hour gets diluted across twenty-three calmer ones. Monsoon dust is also patchy — a wall of it can wrap one side of the basin and miss a neighborhood a few miles off. And the nearest station may sit far from wherever a person is standing.

A calm reading downtown says less about Marana or the east side than it looks like it does. None of that makes the haze fake — one number averages one location, not your block. Monsoon dust and the ozone behind it covers every way a reading and your senses split.

Dust spread across the calendar. 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 Tucson?

The air quality Tucson sees each summer runs on the same monsoon system Phoenix sits in, but the dust doesn’t behave identically in each city. Phoenix’s valley is wide and flat enough for a haboob to cross in one long wall. Tucson’s basin is smaller and more mountain-ringed — Santa Catalinas north, Rincons east, Santa Ritas south, Tucson Mountains west.

A Tucson dust wall generally runs into higher ground sooner — reasoned from geography, not measured; nobody publishes a haboob-length figure for either city. Both cities share the pollutant itself: coarse, wind-lofted PM10 particulate matter, not the fine PM2.5 that dominates wildfire smoke.

Winter runs on a separate mechanism. The same mountains trap cool air near the ground on cold, still nights — a thermal inversion, the mechanism behind Denver’s brown cloud. It holds wood smoke and exhaust down instead of letting them disperse. We haven’t found Tucson-specific reporting on the winter pattern, so this is the general basin mechanism, not a sourced local account.

Is the air safe to breathe in Tucson today?

A Tucson monsoon dust wall can wrap Marana and miss a neighborhood on the east side entirely. The citywide number can read calmer than what’s actually blowing past a person’s own window. Go on ordinary air. Short and unloaded: the short version of the Sabino Canyon loop instead of the full wash. Don’t go once dust pushes the reading into red.

EPA’s everyone-warning starts at 151, Unhealthy, and 201 to 300, Very Unhealthy, is that same warning at a more serious level, not a new group. Past roughly 200, dust wall or clear side of town, the plan moves indoors.

What AQI should you stay inside?

110. That’s one runner’s ceiling, from r/Marathon_Training: “I’ll run in up to 110 because…error bars.” 60 is another number entirely — an asthmatic runner’s, from 156 logged runs against AQI. Past it, “my lungs struggle regardless of how well I’ve trained,” even though EPA calls nothing under 100 unhealthy. Their success rate: 87% under 50, 42% between 50–70, 12% past 70. Parents land near 100.

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

Dust clears fast; smoke doesn’t. A Tucson monsoon wall and a wildfire-smoke event shift the numbers above by different amounts — smoke drags the table down further, about one EPA band. EPA’s category reads 101–150, Unhealthy for Sensitive Groups — attributed, not a verdict on any one reader.

No Arizona rule sets a school or daycare AQI cutoff, at least not one this project has confirmed. Washington’s and Minnesota’s are the only two documented numbers anywhere in the material reviewed. The two states that document a number has both. Ask your own provider what they actually use.

A portable HEPA unit, or a Corsi-Rosenthal box built for roughly $130 in a 12x14 bedroom, is the safer indoor call. Leave the whole-house MERV-13 filter alone until a licensed tech checks the static pressure — an undersized system won’t forgive the swap. What to run indoors when the dust arrives has the setup.

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

Ground-level ozone is invisible and odorless wherever it forms, Tucson included. On a clear, still summer afternoon the reading can run higher than the sky suggests — the same gap that shows up in Phoenix, Denver and Los Angeles. There’s no smelling your way to a safe read on it.

The reverse also happens, on a shorter clock than most expect. A morning hazy from an overnight inversion can read moderate by noon, once the average smooths the spike and the sun burns the inversion off. Checking once, at the wrong hour, gives a different picture than the day actually had.

There’s a third case the AQI doesn’t help with at all: Valley Fever. Coccidioides, the fungus behind it, is endemic across the Sonoran Desert basin, Tucson included. It rides into the air on wind and disturbed dust, independent of whatever the PM2.5 or PM10 numbers say. The AQI does not measure fungal spores at any level; our own methodology page states that plainly. Arizona’s Department of Health Services publishes its own guidance on dust, air quality and Valley Fever specifically — that’s the source to check, not this page.

That’s the monitoring station behind today’s reading — its distance from downtown, and the nearby PurpleAir sensor count. A station miles off under-reports whichever side of the basin sits farthest from it. That’s worst during a monsoon storm the station on the other side never saw. Why a monsoon cell the station never saw still counts goes through it.

Phoenix sits in the same Desert Southwest haboob and monsoon airshed, and so does Albuquerque, further up the same corridor.

FAQ

What’s the air quality forecast for Tucson tomorrow?

Monsoon storms can flip a forecast within hours during summer. Treat it as a direction, not a lock, and recheck the morning of.

What’s the UV index in Tucson today?

UV runs on its own scale, separate from AQI. Tucson's elevation and clear desert skies push UV high most of the year, so a good AQI reading is no reason to skip sunscreen.

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

The air quality Tucson reports moves hardest during an active monsoon storm or wildfire smoke drifting in from outside Arizona. See where the basin sits on the national board right now against every tracked city.

Why does it smell like smoke outside in Tucson?

Blowing dust doesn’t usually carry a smell. Actual smoke is more likely wildfire smoke from Arizona’s forests or another state, not a haboob passing through. Smoke versus blowing dust, and how to tell covers the difference.

Does the Tucson AQI reading account for Valley Fever?

No. The Air Quality Index is built from six pollutants — PM2.5, PM10, ozone, NO2, SO2 and CO — fungal spores aren’t one of them. See “why our number may not match” above, and check Arizona’s Department of Health Services for Valley Fever guidance specifically.