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atmospheric processes that create regional haze and causes ecological damage in 

 class I areas in the East and in Southern California. 



In addition, we are continuing to work on specific source related air quality 

 impacts to our class I areas by monitoring implementation of the Navajo Generating 

 Station sulfur dioxide emission limit requirements EPA set in 1991. We are also 

 working with states, other federal agencies and others on state or region-specific 

 issues; this includes working with the Forest Service and the State of Colorado on 

 issues related to visibility and other air quality-related effects at the Mount Zirkel 

 Wilderness, and working with the National Park Service and representatives of the 

 Government of Mexico concerning visibility protection for the Big Bend National 

 Park. With respect to regional haze conditions, a good starting point for my 

 discussion today is the National Academy of Sciences Report (Protecting Visibility 

 in National Parks and Wilderness Areas . January 1993). Among other things, 

 although the NAS Report stated that there is still some uncertainty regarding the 

 relationship between human activities and visibility, the basic science needed to 

 address regional haze is now available. The Report also concluded that progress 

 towards remedying and preventing visibility impairment in class I areas will require 

 regional programs that operate over large geographic areas and limit emissions of 

 pollutants that can cause regional haze. 



In addition, as required by the Act, EPA issued a Report entitled "Effects of 

 the 1 990 Clean Air Act Amendments on Visibility in Class I Areas: An EPA Report 

 to Congress, October 1993." That Report reviewed requirements of the 

 Amendments, especially those efforts related to acid rain and attainment of the 

 ozone and particulate matter national ambient air quality standards, and estimated 

 changes in regional visibility conditions for class I areas. The EPA Report indicates 

 that, primarily due to the acid rain program, class I areas of the Eastern U.S. 

 should see noticeable improvements in visibility conditions, with the largest 

 improvements likely in the central to southern Appalachian Mountain areas. The 

 Report estimates that in the Western U.S., general growth in emissions related to 



