Systems and methods are provided for portable and compact nitric oxide (NO) generation that can be embedded into other therapeutic devices or used alone. In some embodiments, an ambulatory NO generation system can be comprised of a controller and disposable cartridge. The cartridge can contain filters and scavengers for preparing the gas used for NO generation and for scrubbing output gases prior to patient inhalation. The system can utilize an oxygen concentrator to increase nitric oxide production and compliment oxygen generator activity as an independent device. The system can also include a high voltage electrode assembly that is easily assembled and installed. Various nitric oxide delivery methods are provided, including the use of a nasal cannula.