The Washington 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----------------------------------------------------------------------------------------------------------------Eastern Washington-Northern Idaho Interstate.............. I IA III I IIINorthern Washington Intrastate............................ II III III III IIIOlympic-Northwest Washington Intrastate................... II II III III IIIPortland Interstate....................................... I IA III I IPuget Sound Intrastate.................................... I IA III I ISouth Central Washington Intrastate....................... I III III III III---------------------------------------------------------------------------------------------------------------- [37 FR 10900, May 31, 1972, as amended at 39 FR 16347, May 8, 1974; 45 FR 37836, June 5, 1980]