Final answer:
State and local governments may establish laws that contain stricter requirements than the Clean Air Act/EPA regulations, providing an opportunity to enhance environmental protections beyond federal baselines.
Step-by-step explanation:
The question pertains to the powers of state and local governments in establishing laws related to refrigerants and how these laws relate to federal regulations set by the Clean Air Act and the Environmental Protection Agency (EPA). Specifically, it asks which statement is true regarding the ability of state and local governments to set laws in this area.
Based on the provided information and relevant legislation, state and local governments may establish laws that contain stricter requirements than the Clean Air Act/EPA regulations. This means that while states cannot set regulations that are less stringent than the federal baseline (option 2) or exempt refrigerants from the Clean Air Act (option 4), they can go above and beyond the federal requirements to better protect the environment if they choose to do so (option 3). A notable example of this is the California Air Resources Board, which has set higher emissions standards that have been influential in shaping national policy.