If the department finds, after public hearing upon due notice to all interested parties, that the emissions from a particular type or class of air contaminant source should be regulated on a statewide basis in the public interest and for the protection of the welfare of the citizens of the state, it may adopt and enforce rules to control and/or prevent the emission of air contaminants from such source. An authority may, after public hearing and a finding by the board of a need for more stringent rules than those adopted by the department under this section, propose the adoption of such rules by the department for the control of emissions from the particular type or class of air contaminant source within the geographical area of the authority. The department shall hold a public hearing and shall adopt the proposed rules within the area of the requesting authority, unless it finds that the proposed rules are inconsistent with the rules adopted by the department under this section. When such standards are adopted by the department it shall delegate solely to the requesting authority all powers necessary for their enforcement at the request of the authority. If after public hearing the department finds that the regulation on a statewide basis of a particular type or class of air contaminant source is no longer required for the public interest and the protection of the welfare of the citizens of the state, the department may relinquish exclusive jurisdiction over such source.