Persons ineligible to membership on boards or employment by district

Any person having any interest in the sale or control of any air pollution prevention equipment or apparatus which might be used effectively to reduce the emission of air contaminants shall not be eligible to be a member of an air pollution control board or of a hearing board, or to be the secretary-treasurer of an air pollution control board, or an air pollution control officer, or any assistant, deputy, clerk, attache, or employee of an air pollution control officer or secretary-treasurer, or to be any other employee of an air pollution control board or district.