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In 1995, the IMPROVE (Interagency Monitoring of Protected Visual Environments) Steering Committee, including the U.S. Forest Service, formed a consensus that five years of scene monitoring yields sufficient examples of most visual air quality conditions. To secure a representative set of observed air quality conditions for each scene monitoring site, a series of slides is selected from the period of record and archived on CD-ROM. This series of slides makes up the historical photographic archive and consists of:


          A spectrum series of regional haze visibility conditions observed at the site for each monitored time of day.


          A selection of the cleanest clear sky slides to represent seasonal pristine conditions for each monitoring season.


          Selected visibility and meteorological episodes or events observed during the period of record (including wildfire, winter inversions, and/or regional haze impacts).


          Selected layered haze events observed during the period of record.


          Specific slides that show scenic views of the vista and observations of meteorological interest during the period of record.


          Historical slide selections requested by the U.S. Forest Service and/or other air quality managers that depict visibility conditions for project-specific reports or public presentations.

The total number of slides selected for each historical archive depends on the vista, the variability in visual air quality, the period of record, and completeness of the slide database. Final sets can vary from 50 to 150 slides. Historical slide archives for each site are reproduced digitally to Kodak Photo CD (PCD) format and transfered to a Kodak Gold CD. Master historical photographic archives produced for each site contain 4 JPEG resolutions of each selected image (Image Gallery); graphic images of the monitoring location and site vistas (Site Specifications); as well as associated cumulative frequency summaries, tables, and/or data listings (Spectrum Frequencies).





Air Resource Specialists, Inc. created this historical photographic archive for the U.S. Forest Service Air Monitoring Program. The U.S. Forest Service is the copyright owner of all provided images. Any commercial use or duplication of this material without prior approval or licensing is forbidden. Use of the provided images should reference the U.S. Forest Service Air Monitoring Program. Additional information regarding the U.S. Forest Service Air Program can be obtained by accessing the Forest Service National Air Program Web site at Additional information regarding the IMPROVE and National Park Service air quality programs can be obtained by accessing the NPS AIRWeb site at http://




Prepared by Air Resource Specialists, Inc.

Under USFS Contract 53-82FT-7-03


For additional information contact:
Air Resource Specialists, Inc.
1901 Sharp Point Drive
Suite E
Fort Collins, CO 80525
Ph: 970.484.7941
Fx: 970.484.3423