LAFD Air Ambulance
LA City FD Air Ambulance dispatches are on either LAFD OCD 8 or LAFD OCD 7. OCD 8 is used for San Fernando Valley Responses, and OCD 7 is used for Metro LA areas (south of Mulholland Drive).
LA County Fire dispatches are done on LACoFD Blue 8, along with the rest of the county's dispatches. Most of the calls are either in the Antelope or San Gabriel Valley areas. For those, you can listen to the command channel on Blue 12 (Santa Clarita and AV) or Blue 6 (San Gabriel Valley). The helicopters also are almost always on Tac 19 (154.400) when in the air. For Blue 8 dispatches, they are always toned out using the two-tone system. So, if you are passively listening to Blue 8, you should perk your ears up when you hear the tones. The Chiefs and some other specialized units also have tones, so you will also hear those.