40 C.F.R. § 52.1521 — Classification of regions.
§ 52.1521 Classification of regions. The New Hampshire plan was evaluated on the basis of the following classifications: Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone Androscoggin Valley Interstate IA III III III III Central New Hampshire Intrastate III III III III III Merrimack Valley—Southern New Hampshire Interstate I III III III I [37 FR 10879, May 31, 1972, as amended at 45 FR 24876, Apr. 11, 1980; 80 FR 78141, Dec. 16, 2015; 81 FR 44554, July 8, 2016]