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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 12/20/25 (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 +]		 LNGM Moderate 56 Particulate < 10 micrometers 66 µg/m3 24-hour 2 AM
Ft. Collins - Greeley
[expand +]		 FTCW Good 40 Ozone 43 PPB 8-hour 1 AM
Colorado Springs
[expand +]		 ACAD Good 40 Ozone 43 PPB 8-hour 1 AM
Grand Junction
[expand +]		 GJPB Moderate 60 Particulate < 2.5 micrometers 13 µg/m3 24-hour 4 PM
Pueblo
[expand +]		 PWES Good 39 Ozone 42 PPB 8-hour 2 AM
Colorado River Valley
[expand +]		 RIFL Good 33 Particulate < 2.5 micrometers 6 µg/m3 24-hour 4 AM
Four Corners
[expand +]		 CTZ Good 33 Ozone 36 PPB 8-hour 6 PM
Steamboat Springs
[expand +]		 SSMB Good 33 Particulate < 10 micrometers 36 µg/m3 24-hour 4 AM
Aspen
[expand +]		 ASPN Good 35 Ozone 38 PPB 8-hour 6 PM
Other
[expand +]		 DELT Moderate 51 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 Good 48 0.049 0.044 3 PM

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