The LIF-NO instrument uses single-photon laser induced fluorescence to achieve fast, precise and accurate measurements of nitric oxide down to sub-pptv mixing ratios. The instrument is designed as a two-channel instrument and the second channel can be used to detect other species that can be converted into NO, such as NO2 or NOy. Measurements of reactive nitrogen species provide important constraints on radical oxidation chemistry, ozone destroying chemistry, and are useful tracers of pollution.