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Banner with Colorado and CDPHE logos on left with text on right reading Colorado Air Quality with Department of Public Health and Environment on the next line.

Detailed Air Quality Summary for 12/31/25 (Yesterday)

Learn more about monitoring sites: site descriptions and
real-time monitoring map

All data are collected real-time and have not been corrected nor validated.

Daily Highs:

Area Site Air Quality Max AQI Pollutant Conc. Period Time *
(MST)
Denver METRO
[expand +]		 I25DEN Moderate 58 Particulate < 2.5 micrometers 12 µg/m3 24-hour 11 AM
Ft. Collins - Greeley
[expand +]		 GREH Moderate 63 Particulate < 2.5 micrometers 15 µg/m3 24-hour 11 PM
Colorado Springs
[expand +]		 MAN Good 35 Ozone 38 PPB 8-hour 5 PM
Grand Junction
[expand +]		 GJPB Moderate 54 Particulate < 2.5 micrometers 10 µg/m3 24-hour 7 PM
Pueblo
[expand +]		 PWES Good 30 Ozone 32 PPB 8-hour 5 PM
Colorado River Valley
[expand +]		 RIFL Good 25 Particulate < 2.5 micrometers 4 µg/m3 24-hour 12 AM
Four Corners
[expand +]		 PAG Good 25 Particulate < 2.5 micrometers 4 µg/m3 24-hour 12 AM
Steamboat Springs
[expand +]		 SSMB Good 39 Particulate < 2.5 micrometers 7 µg/m3 24-hour 7 PM
Aspen
[expand +]		 ASPN2 Good 39 Particulate < 2.5 micrometers 7 µg/m3 24-hour 12 AM
Other
[expand +]		 ALA Moderate 52 Particulate < 2.5 micrometers 9 µg/m3 24-hour 12 AM

Area Site Visibility Max VSI 4-hour Average
(1/km)
 Beta Extinction
(1/km)
 Time *
(MST)
Denver DES Moderate 69 0.060 0.062 12 PM

* All data are reported in Mountain Standard Time (MST). During daylight savings time add one hour to the reported hour.