Systems and methods for nitric oxide generation are provided. In an embodiment, an NO generation system can include a controller and disposable cartridge that can provide nitric oxide to two different treatments simultaneously. The disposable cartridge has multiple purposes including preparing incoming gases for exposure to the NO generation process, scrubbing exhaust gases for unwanted materials, characterizing the patient inspiratory flow, and removing moisture from sample gases collected. Plasma generation can be done within the cartridge or within the controller. The system has the capability of calibrating NO and NO2 gas analysis sensors without the use of a calibration gas.