Arizona air quality

Pima County, Arizona Air Quality

Pima County32.097, -111.790

The nearest reporting area, Rillito, measured an index of 22 this hour, which is Good. Arizona Department of Environmental Quality forecasts Good for Rillito today and Good tomorrow.

Measured now
22 · Good
Today
24 · Good
Tomorrow
28 · Good
Pollutant
PM10

Fine particles on the map

Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over Pima County, Arizona. Open it for the live map, where it pans and zooms.

Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over Pima County, Arizona Open the live map with the particulate forecast

Map layer from NOAA National Air Quality Forecast Capability. Boundaries from the Iowa Environmental Mesonet.

Alerts in force

An Air Quality Alert is issued by the National Weather Service on behalf of a state or local agency when pollution is expected to reach a level that harms health. An Air Stagnation Advisory means the air will not move enough to clear what is already in it.

None are in force near Pima County right now. All Arizona warnings.

Now

Good

Reporting area
Rillito, AZ, 43 miles away
Reported by
Arizona Department of Environmental Quality
Area index
22 · Good

Measured, not modeled. AirNow observations are preliminary until the operating agency certifies them, which happens months later.

Today and tomorrow

Arizona Department of Environmental Quality's own forecast for Rillito, written by a forecaster rather than read off a model.

DayCategoryIndexPollutant
TodayGood24PM10
TomorrowGood28PM10

The forecaster’s discussion

Written by Arizona Department of Environmental Quality for Rillito and filed with AirNow.

A fall-like atmospheric pattern will affect Arizona's weather over the next several days as two low-pressure waves will pass through the region. Compared to a richly moist, monsoon environment, conditions in southeastern Arizona will be relatively dry. However, the monsoon isn't about to go down without a fight. Storm/rain chances look to be possible on Tuesday as the monsoon high pressure tries to expand into the area again. But, the monsoon's days are numbered.

As for PM10 (dust), PM10 will easily remain in the Good AQI category each day because of the recent rain. But, we can't rule out locally elevated PM10 levels from morning local activities.

Check back again on Monday for the next forecast.

M. Graves

Last Update: Friday, September 18, 2026, 8:58 AM

Hour by hour

NOAA’s National Air Quality Forecast Capability, bias-corrected against monitors, for this town’s own coordinate. The worst hour ahead is an index of 32, Good, around Wed, 6:00 PM MST, from the run issued Sun, 11:00 PM MST. This is a model, not a measurement.

HourIndexCategoryPM2.5Ozone
Mon, 1:00 AM MST15Good2.1
Mon, 2:00 AM MST12Good1.9
Mon, 3:00 AM MST11Good1.7
Mon, 4:00 AM MST8Good1.2
Mon, 5:00 AM MST10Good2.1
Mon, 6:00 AM MST9Good1.5
Mon, 7:00 AM MST15Good2.816.5
Mon, 8:00 AM MST15Good2.616.5
Mon, 9:00 AM MST16Good2.417
Mon, 10:00 AM MST17Good2.918.2
Mon, 11:00 AM MST19Good2.720.2
Mon, 12:00 PM MST20Good222.6
Mon, 1:00 PM MST22Good1.624.9
Mon, 2:00 PM MST25Good0.827.2
Mon, 3:00 PM MST27Good0.929.2
Mon, 4:00 PM MST28Good0.830.9
Mon, 5:00 PM MST29Good0.832
Mon, 6:00 PM MST30Good0.632.4
Mon, 7:00 PM MST29Good1.431.6
Mon, 8:00 PM MST28Good0.430.1
Mon, 9:00 PM MST26Good0.828.3
Mon, 10:00 PM MST24Good126.7
Mon, 11:00 PM MST23Good1.625.2
Tue, 12:00 AM MST21Good1.923.7
Tue, 1:00 AM MST20Good1.322.1
Tue, 2:00 AM MST19Good0.820.4
Tue, 3:00 AM MST18Good0.419.2
Tue, 4:00 AM MST17Good1.418.5
Tue, 5:00 AM MST16Good1.717.9
Tue, 6:00 AM MST15Good1.316.9
Tue, 7:00 AM MST14Good2.615.8
Tue, 8:00 AM MST13Good2.615
Tue, 9:00 AM MST13Good2.315
Tue, 10:00 AM MST14Good1.815.5
Tue, 11:00 AM MST15Good1.516.2
Tue, 12:00 PM MST16Good117.2
Tue, 1:00 PM MST17Good1.618.4
Tue, 2:00 PM MST19Good1.820.2
Tue, 3:00 PM MST20Good1.822.3
Tue, 4:00 PM MST22Good1.524.6
Tue, 5:00 PM MST24Good0.926.5
Tue, 6:00 PM MST26Good0.828.4
Tue, 7:00 PM MST27Good1.329.8
Tue, 8:00 PM MST28Good1.430.8
Tue, 9:00 PM MST29Good1.231.5
Tue, 10:00 PM MST29Good1.331.9
Tue, 11:00 PM MST30Good1.432
Wed, 12:00 AM MST29Good1.531.7
Wed, 1:00 AM MST29Good1.331.1
Wed, 2:00 AM MST27Good129.9
Wed, 3:00 AM MST26Good0.629
Wed, 4:00 AM MST26Good0.428
Wed, 5:00 AM MST25Good1.427.1
Wed, 6:00 AM MST24Good126.1
Wed, 7:00 AM MST22Good1.524.8
Wed, 8:00 AM MST21Good1.423.9
Wed, 9:00 AM MST21Good1.323.6
Wed, 10:00 AM MST21Good1.423.9
Wed, 11:00 AM MST22Good1.124.8
Wed, 12:00 PM MST24Good1.226
Wed, 1:00 PM MST25Good1.527.7
Wed, 2:00 PM MST27Good129.5
Wed, 3:00 PM MST29Good0.731.6
Wed, 4:00 PM MST31Good0.433.4
Wed, 5:00 PM MST31Good0.334.6
Wed, 6:00 PM MST32Good0.535.4
Wed, 7:00 PM MST32Good0.835.4
Wed, 8:00 PM MST31Good0.734.7
Wed, 9:00 PM MST31Good2.334.2
Wed, 10:00 PM MST31Good3.633.8
Wed, 11:00 PM MST31Good3.833.5

Fine particles in micrograms per cubic meter, ozone in parts per billion as an 8-hour average. The index for each hour is EPA’s: the ozone figure is already the 8-hour average the ozone index is defined on, and the particle figure is run through EPA’s NowCast, which is how an hourly PM2.5 concentration becomes an index.

Smoke

NOAA’s analysts have not drawn smoke over Pima County in satellite imagery today.

NOAA’s model forecasts near-surface smoke peaking at 0.2 µg/m³ around Tue, 8:00 PM MST.

Smoke on the radar over Pima County

What this means

Good

Air quality is satisfactory, and air pollution poses little or no risk.

Who is affected
Nobody is expected to be affected.
What to do
It is a good day to be outside.
Index range
0 to 50

Category descriptions are the Environmental Protection Agency’s own.

What these numbers are. An index beside a monitor’s name is a measurement, published hourly by AirNow and preliminary until the operating agency certifies it. A category for today or tomorrow is a state or local agency forecaster’s own forecast for a reporting area. An hourly index is NOAA’s air quality model on a five-kilometer grid, not a reading from any instrument. Where a town has no monitor within reach, only the model figures appear, and the page says so.

Nearby

The nearest towns with a page of their own, closest first.

Weather forecast for Pima CountyWarnings in Pima CountyLive radar over Pima CountyArizona air quality

Sources

Observations and daily forecasts from AirNow, the US Environmental Protection Agency’s program with NOAA, the National Park Service, NASA, tribal, state and local agencies. Hourly forecasts from NOAA’s National Air Quality Forecast Capability. Smoke analysis from NOAA’s Hazard Mapping System. Alerts from the National Weather Service. Index categories and breakpoints are EPA’s, as revised in 2024.