(a) Upon written application by a source owner or operator, the commissioner may exempt the source owner or operator from the provisions of section 224.4(a) of this Part, and set forth alternative stack monitoring and reporting requirements if the source owner or operator can demonstrate that:

(b) Where it can be shown to the commissioner's satisfaction that an emission source subject to this Part, for which an application for a permit to construct was received prior to August 17, 1971, cannot comply with the requirements of this Part for technological or economic reasons, the commissioner may except the source owner from the requirement of this Part and accept a lesser degree of control upon submission of satisfactory evidence by the source owner.