The department of health shall adopt, amend, and repeal rules under chapter 91 for the regulation of ambulances within the State, including but not limited to the certification of vehicles, equipment, supplies, and communications systems; provided that any county operating a county emergency medical services system pursuant to part of chapter 46 shall be responsible for the purchase, maintenance, and servicing of all vehicles, equipment, supplies, and communication systems operated for emergency services within the county. The department may contract to certify air and ground ambulance units statewide. The department may charge a reasonable fee for annual certification and safety inspections of air and ground ambulances. Any person who provides emergency medical service as an employee of any emergency ambulance service statewide shall be subject to chapter 453.