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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 09/15/26 (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 +]		 NREL Moderate 64 Ozone 59 PPB 8-hour 6 PM
Ft. Collins - Greeley
[expand +]		 FTCF Moderate 53 Particulate < 2.5 micrometers 10 µg/m3 24-hour 12 AM
Colorado Springs
[expand +]		 ACAD Good 44 Ozone 47 PPB 8-hour 5 PM
Grand Junction
[expand +]		 PAL Good 39 Ozone 42 PPB 8-hour 6 PM
Pueblo
[expand +]		 PWES Good 37 Ozone 40 PPB 8-hour 6 PM
Colorado River Valley
[expand +]		 RIFLO3 Good 32 Ozone 35 PPB 8-hour 6 PM
Four Corners
[expand +]		 CTZ Good 44 Ozone 47 PPB 8-hour 6 PM
Steamboat Springs
[expand +]		 SSMB Good 19 Particulate < 2.5 micrometers 3 µg/m3 24-hour 8 AM
Aspen
[expand +]		 ASPN2 Good 12 Particulate < 2.5 micrometers 2 µg/m3 24-hour 10 PM
Other
[expand +]		 LMB Good 25 Particulate < 10 micrometers 27 µg/m3 24-hour 12 AM

Area Site Visibility Max VSI 4-hour Average
(1/km)
 Beta Extinction
(1/km)
 Time *
(MST)
Denver DES Poor 110 0.083 0.080 11 AM

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