The Illinois 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----------------------------------------------------------------------------------------------------------------Burlington-Keokuk Interstate.............................. I I III III IIIEast Central Illinois Intrastate.......................... III II III III IIIMetropolitan Chicago Interstate (Indiana-Illinois)........ I I I I IMetropolitan Dubuque Interstate........................... I III III III IIIMetropolitan Quad Cities Interstate....................... I III III III IIIMetropolitan St. Louis Interstate (Missouri-Illinois)..... I I III I INorth Central Illinois Intrastate......................... II IA III III IIIPaducah (Kentucky)-Cairo (Illinois) Interstate............ I II III III IIIRockford (Illinois)-Janesville-Beloit (Wisconsin) II III III III III
Interstate...............................................Southeast Illinois Intrastate............................. III II III III IIIWest Central Illinois Intrastate.......................... I IA III III III---------------------------------------------------------------------------------------------------------------- [37 FR 10862, May 31, 1972, as amended at 39 FR 16346, May 8, 1974; 45 FR 11493, Feb. 21, 1980]