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constituents developed under Project MOHAVE with the technical committees of 

 the Commission. 



EPA is also modifying the regional acid deposition model (RADM) to more 

 completely address particle concentration and size. This research will expand our 

 capabilities to model the impacts of these emissions on visibility, ozone, and 

 particulate matter concentrations. In addition, we are continuing our support of 

 monitoring in class I areas as part of the Interagency Monitoring of Protected 

 Visual Environments (IMPROVE) program. Since 1987, IMPROVE has deployed 

 monitors to track visibility impairment and related pollutant levels in class I areas. 

 This effort has been expanded to monitor more sites in the East, including state- 

 sponsored monitoring, and has provided technical assistance to states and other 

 countries on appropriate visibility monitoring techniques. 



As required by section 1 69B, when the Grand Canyon Visibility Transport 

 Commission report is submitted to EPA, the Administrator will have eighteen 

 months to address regional haze regulations, taking into consideration the 

 Commission report, other studies and other relevant information. We anticipate 

 the Commission report will provide a framework for addressing regional haze on 

 the Colorado Plateau. That framework may also be suitable to address regional 

 haze problems in other class I areas. 



We anticipate that in the Eastern U.S., most of the emphasis at EPA for 

 protecting class I area air quality will be linked to implementation of the acid rain 

 control provisions. I want to emphasize that the key component to making 

 immediate progress on improving visibility and other air quality related values in the 

 eastern class I areas is, first and foremost, full implementation of the Phase II 

 provisions under the Act's acid deposition control program. Only with full 

 implementation will we hope to realize the estimated improvements noted in our 

 report to Congress. However, it is also clear that after full implementation of the 

 acid rain program, there will be the need to develop other programs to assure 

 reasonable progress towards the Congressionally established national visibility goal. 



