Visibility Standard

« Back to Glossary Index

A visibility standard is a measure of visual air quality. Colorado’s visibility standard, as established by the state legislature, requires that not more than 7.6 percent of the light across a path of a kilometer in length of air be extinguished, averaged daily over four daylight hours. The standard is equivalent to a visual range of 32 miles and was established by the CDPHE after assessing public perception and values on visual aesthetics.