PUBLIC LAW 101-549—NOV. 15, 1990 104 STAT. 2695 mum extent practicable, utilize resources of Mexico where such utilization would reduce costs to the United States. Such funding agreements shall include authorization for the Administrator to— (1) review and agree to plans for monitoring and remediation; (2) inspect premises, equipment and records to insure compliance with the agreements established under and the purposes set forth in this section; and (3) where necessary, develop grant agreements with affected States to carry out the provisions of this section. SEC. 816. VISIBILITY. Subpart 2 of part C of title I of the Clean Air Act is amended by adding the following new section at the end thereof: "SEC. 169B. VISIBILITY. 42 USC 7492. "(a) STUDIES.— (1) The Administrator, in conjunction with the National Park Service and other appropriate Federal agencies, shall conduct research to identify and evaluate sources and source regions of both visibility impairment and regions that provide predominantly clean air in class I areas. A total of $8,000,000 per year for 5 years is authorized to be appropriated for the Environmental Protection Agency and the other Federal agencies to conduct this research. The research shall include— "(A) expansion of current visibility related monitoring in class I areas; "(B) assessment of current sources of visibility impairing pollution and clean air corridors; "(C) adaptation of regional air quality models for the assessment of visibility; "(D) studies of atmospheric chemistry and physics of visibility. "(2) Based on the findings available from the research required in subsection (a)(1) as well as other available scientific and technical data, studies, and other available information pertaining to visibility source-receptor relationships, the Administrator shall conduct an assessment and evaluation that identifies, to the extent possible, sources and source regions of visibility impairment including natural sources as well as source regions of clear air for class I areas. The Administrator shall produce interim findings from this study within 3 years after enactment of the Clean Air Act Amendments of 1990. "(b) IMPACTS OF OTHER PROVISIONS.— Within 24 months after enactment of the Clean Air Act Amendments of 1990, the Administrator shall conduct an assessment of the progress and improvements in visibility in class I areas that are likely to result from the implementation of the provisions of the Clean Air Act Amendments of 1990 other than the provisions of this section. Every 5 years thereafter the Administrator shall conduct an sissessment of actual progress and improvement in visibility in class I areas. The Administrator shall prepare a written report on each assessment and transmit copies of these reports to the appropriate committees of Congress. " (c) ESTABLISHMENT OF VISIBILITY TRANSPORT REGIONS AND COMMISSIONS.— "(1) AUTHORITY TO ESTABLISH VISIBILITY TRANSPORT REGIONS. — Whenever, upon the Administrator's motion or by petition from the Governors of at least two affected States, the Administrator has reason to believe that the current or projected interstate
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