Any proposed ordinance may be enacted as an emergency ordinance if the county council finds as a fact, and states in the ordinance, that the ordinance is necessary for the immediate preservation of public peace, health or safety or for the support of county government and its existing public institutions. A minimum of four affirmative votes shall be required to enact an emergency ordinance. Emergency ordinances shall not be subject to the veto power of the county executive. All emergency ordinances shall be effective immediately upon passage by the county council.