CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 52—APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS > SUBPART I—Delaware (§52.420 to §52.465) > 52.421—Classification of regions.

52.421—Classification of regions.

The Delaware 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)
Metropolitan Philadelphia Interstate I I III I I
Southern Delaware Intrastate III III III III III

Code of Federal Regulations

[37 FR 10856, May 31, 1972, as amended at 39 FR 16345, May 8, 1974]