(a) The requirements of this Subpart apply, in nonattainment areas and attainment areas of the State within the ozone transport region, to the construction and/or operation of:

(b) An existing non-major facility that is located in a nonattainment area or an attainment area of the State within the ozone transport region which proposes a modification that has a project emission potential for any nonattainment contaminant that does not equal or exceed the applicable major facility threshold, in tables 1 or 2 of Subpart 231-13 of this Part, but would result in the facility becoming a major facility for such contaminant, is not subject to review under this Subpart. However, the facility owner or operator must apply for and obtain a permit in accordance with Part 201 of this Title and the permit must contain an emission limit(s) equal to the potential to emit of the emission source(s) affected by the modification.