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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 09/16/25 (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 +]		 AURE Moderate 51 Ozone 55 PPB 8-hour 6 PM
Ft. Collins - Greeley
[expand +]		 TIM Good 47 Ozone 51 PPB 8-hour 5 PM
Colorado Springs
[expand +]		 ACAD Good 47 Ozone 51 PPB 8-hour 5 PM
Grand Junction
[expand +]		 PAL Good 47 Ozone 51 PPB 8-hour 8 PM
Pueblo
[expand +]		 PWES Good 49 Ozone 53 PPB 8-hour 6 PM
Colorado River Valley
[expand +]		 RIFLO3 Good 39 Ozone 42 PPB 8-hour 8 PM
Four Corners
[expand +]		 CTZ Good 44 Ozone 48 PPB 8-hour 6 PM
Steamboat Springs
[expand +]		 SSMB Good 21 Particulate < 2.5 micrometers 3 µg/m3 24-hour 2 PM
Aspen
[expand +]		 ASPN Good 37 Ozone 40 PPB 8-hour 6 PM
Other
[expand +]		 LMB Good 28 Particulate < 2.5 micrometers 5 µg/m3 24-hour 6 PM

Area Site Visibility Max VSI 4-hour Average
(1/km)
 Beta Extinction
(1/km)
 Time *
(MST)
Denver DES Moderate 71 0.061 0.048 11 AM

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