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(4) Are nitrogen oxides being effectively regulated through 

 the PSD program ? 



Nitrogen oxides (N0 X ) are not being effectively regulated 

 through the PSD program. The Great Smoky Mountains National Park 

 is suffering from excessive nitrification which adversely effects 

 vegetation and aquatic resources. Furthermore, both the Smokies 

 and Shenandoah suffer from excessive ozone levels that damage 

 vegetation and threaten human health. In the ODEC appeal, we 

 challenged the state and EPA's failure to regulate N0 X as a 

 precursor to ozone and the failure to consider N0 X emissions' 

 impacts on nitrification of soils and waterbodies such as the 

 Chesapeake Bay. The ODEC decision confirmed that EPA was not 

 reguiring an assessment of the effects of N0 X emissions on ozone 

 levels, vegetation, or the Chesapeake Bay. EPA indicated in the 

 decision it was considering reassessing the policy of not 

 considering N0 X emissions' impacts on ozone levels. ODEC at 22. 



The time has come for EPA to establish a regulatory program 

 that will ensure that N0 X emissions do not continue to exacerbate 

 ozone problems, aguatic resource degradation, and injury to 

 vegetation. EPA should take aggressive action to address NO x 

 emissions. First, EPA should use its broad authority to protect 

 Class I areas and other resources from the adverse impacts of air 

 pollution and establish a N0 X cap at a level well below current 

 levels that will provide protection to Class I areas and their 

 air quality-related values and to other important resources such 

 as the Chesapeake Bay. The National Research Council of the 

 National Academy of Sciences has documented the role of N0 X 

 emissions in rural ozone pollution. See "Rethinking the Ozone 

 Problem in Urban and Regional Air Pollution" (1991) . EPA should 

 use its broad authority under Section 166 of the Clean Air Act to 

 establish such a cap. Under a cap approach, new sources would 

 have to offset their N0 X emissions by providing reductions in N0 X 

 emissions from existing sources. 



Another approach would be to treat an area suffering adverse 

 impacts from ozone or nitrogen deposition resulting from N0 X 

 emissions as a non-attainment area. The federal land managers 

 could establish critical loads for Class I areas and once those 

 levels are exceeded (as they most certainly are in Shenandoah and 

 the Smokies) , new sources would have to get offsets and the 

 states with EPA's assistance would have to establish 

 implementation plans to remedy the adverse impacts. Section 166 

 again provides broad authority for protecting the air quality 

 values of Class I areas. 



Other mechanisms include establishing a secondary standard 

 for ozone that would be protective of the air guality-related 

 values in Class I areas. Once again, if that standard was 

 violated, the sources, both existing and new, would be treated as 

 if they were in a non-attainment area due to the violation of the 



