the Act and the significant problem of dealing with nonattainment required 

 more stringent SIP's and more active enforcement activities than originally 

 anticipated. The CAA of 1970 was amended in 1977. 



The 1977 Amendments to the Clean Air Act 



The Amendments of 1977 to the Clean Air Act have been described as a compromise 

 neither stronger nor weaker than the intentions of the original act. Although 

 deadlines have been relaxed and some requirements deleted, more standards 

 were imposed and new enforcement policies have been added. 



The mechanism for the implementation of the Clean Air Act still focuses on 

 the State Implementation Plans, however, revisions in the SIP's were required. 

 The revised SIP's must include requirements for the use of all Reasonably 

 Available Control Technologies (RACT) for sources in nonattainment areas, 

 must include an inventory of actual emissions from all sources and must 

 require new construction permits for all new sources (National Air Coalition 

 1977). In nonattainment areas states must have an approved implementation 

 plan revision by 1 July, 1979, which provides for meeting primary air 

 quality standards by 31 December, 1982. 



In attainment areas (areas which meet the NAAQS), the Amendments of 1977 

 call for the Prevention of Significant Deterioration of the ambient air 

 quality. These areas are classified as Class I, Class II, or Class III, 

 depending on the current quality of the air and the degree of deterioration 

 to be allowed. For these nondegradation areas, maximum allowable increases 

 (increments) in ambient concentrations of pollutants have been set. Class I 

 areas include all international parks, national wilderness areas, and 

 national memorial parks greater than 2429 ha (6000 acres) and are most highly 

 protected. Other nondegradation areas are classified Class II and Class III. 

 New sources requesting to site or potentially affect a nondegradation area 

 must comply with PSD requirements. These new sources may be required to 

 employ Best Available Control Technology (BACT) . 



Overview 



The Clean Air Act of 1970 was an ambitious piece of legislation which focused 

 together all previous attempts to clean the Nation's air into one package. 

 The EPA was authorized to set regulations and standards for improving and 

 maintaining air quality in the United States. This included establishing 

 National Ambient Air Quality Standards, dividing the country into Air Quality 

 Control Regions, determining the status of air quality in those regions, 

 developing State Implementation Plans to maintain and improve air quality, and 

 setting New Source Performance Standards. The bulk of the problem of devising 

 methodologies for improving and maintaining air quality was left to the indiv- 

 idual states. Maine responded by proposing a State Implementation Plan for 

 Air Quality in May, 1979, which detailed the strategy for protecting the 

 citizens and ecosystems of Maine from deteriorating air quality. 



3-C-4 



