Property of an authority is public property devoted to an essential public and governmental function and purpose. Income of the authority is considered to be for a public and governmental purpose. The property of the authority and its income and operation are exempt from all taxes and special assessments of this state or a local unit of government of this state. Bonds or notes issued by the authority, and the interest on and income from those bonds and notes, are exempt from all taxation of this state or a local unit of government.