The Rhode Island plan was evaluated on the basis of the following classifications: ----------------------------------------------------------------------------------------------------------------
Pollutant
-----------------------------------------------------
Air quality control region Particulate Sulfur Nitrogen Carbon
matter oxides dioxide monoxide Ozone----------------------------------------------------------------------------------------------------------------Metropolitan Providence Interstate........................ I I III I I---------------------------------------------------------------------------------------------------------------- [37 FR 10891, May 31, 1972, as amended at 38 FR 34325, Dec. 13, 1973; 39 FR 16347, May 8, 1974; 46 FR 25460, May 7, 1981]