The Oklahoma plan was evaluated on the basis of the following classifications: ----------------------------------------------------------------------------------------------------------------
Pollutant
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Air quality control region Particulate Sulfur Nitrogen Carbon
matter oxides dioxide monoxide Ozone----------------------------------------------------------------------------------------------------------------Central Oklahoma Intrastate............................... I III III III INortheastern Oklahoma Intrastate.......................... I III III III ISoutheastern Oklahoma Intrastate.......................... III III III III IIINorth Central Oklahoma Intrastate......................... III III III III IIISouthwestern Oklahoma Intrastate.......................... III III III III IIINorthwestern Oklahoma Intrastate.......................... III III III III IIIMetropolitan Fort Smith Interstate........................ II III III III IIIShreveport-Texarkana-Tyler Interstate..................... II III III III III---------------------------------------------------------------------------------------------------------------- [37 FR 10887, May 31, 1972, as amended at 45 FR 9741, Feb. 13, 1980]