40 C.F.R. § 52.2721
Classification of regions.
Cite as 40 C.F.R. § 52.2721 (2026)
The Puerto Rico plan was evaluated on the basis of the following classifications. Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Photochemical oxidants (hydrocarbons) Puerto Rico IA IA III III III [37 FR 10905, May 31, 1972]