Various systems and devices for generating nitric oxide are disclosed herein. According to one embodiment, the device includes a body having an inlet, an outlet, and a porous solid matrix positioned with the body. The porous solid matrix is coated with an aqueous solution of an antioxidant, wherein the inlet is configured to receive a gas flow and fluidly communicate the gas flow to the outlet through the solid matrix to convert nitrogen dioxide in the gas flow into nitric oxide. The porous solid matrix allows the device to be used in any orientation. Additionally, the porous solid matrix provides a rigid structure suitable to withstand vibrations and abuse without compromising device functionality.