The members of the Board shall be citizens of the Commonwealth and shall be selected from the Commonwealth at large on the basis of merit without regard to political affiliation. Members shall, by their education, training, or experience, be knowledgeable of air quality control and regulation, and shall be fairly representative of conservation, public health, business, and agriculture. No person appointed to the Board shall be employed by persons subject to permits or enforcement orders of the Board or receive a significant portion of his income, whether directly or indirectly, from persons subject to permits or enforcement orders of the Board. Income from a vested retirement benefit shall not be considered income for purposes of this section. Notwithstanding any other provision of this section relating to Board membership, the qualifications for Board membership shall not be more strict than those that are required by federal statute or regulations of the United States Environmental Protection Agency. The provisions of this section shall be in addition to the requirements of the State and Local Government Conflict of Interests Act (§ 2.2-3100 et seq.).