15 



certain visibility impairment episodes in the Grand Canyon, other 

 more remote sources also contribute to the problem. 



EFFORTS TO ADDRESS VISIBILITY IMPAIRMENT 

 CAUSED BY REGIONAL SOURCES HAVE BEEN LIMITED 



Modeling studies conducted by EPA and the Park Service 

 suggest that regional sources may at times account for over 80 

 percent of the visibility problems in some class I areas. To 

 address these regional sources, in 1980 EPA announced its 

 intention to issue regulations to control air pollution within a 

 broad region surrounding class I areas . The agency deferred 

 issuing the regulations, however, until sufficient scientific 

 data on which to base the regulations became available. Despite 

 findings by the National Research Council of the National Academy 

 of Sciences and the Park Service that adequate scientific data 

 exists to begin developing regional haze regulations, EPA 

 officials told us they are not certain that the regulations are 

 needed and are waiting for additional information before reaching 

 a final decision. 



Additional Research Undertaken 



But Monitoring Has Been Curtailed 



The 1990 amendments required EPA, working with the Park 

 Service and other federal agencies, to significantly expand its 

 research and monitoring activities to address visibility 

 impairment problems in class I areas and authorized $8 million 

 per year for 5 years for this purpose. EPA and Park Service 

 visibility funding has increased since enactment of the 1990 

 amendments to support a number of research and monitoring 

 efforts, including the Mohave Project 3 , the Grand Canyon 



3 The Mohave Project is a study of the emissions from the Mohave power 

 plant and their impact on visibility in class I areas in southwestern states. 



