Interagency Monitoring of Protected
Parks and Wilderness Areas possess many stunning vistas and scenery. Unfortunately, these
scenes are diminished by uniform haze
causing discoloration and loss of texture and visual range.
Layered hazes and
plume blight also
detract from the scene. Recognizing the importance ofvisual
air quality, congress included legislation in the
1977 Clean Air Act to prevent future and remedy existing visibility
impairment in Class I areas.
To aid the implementation of this legislation, the IMPROVE program
was initiated in 1985. This program implemented an extensive long term
monitoring program to establish the current visibility conditions, track
changes in visibility and determine causal mechanism for the visibility
impairment in the National Parks and Wilderness Areas.
purpose of this website is to provide access to the IMPROVE monitoring
data resources and educational material on the science of visibility and
First time visitors should visit the Overview section which summarizes the IMPROVE network and visibility
science and regulations.