This work describes the development of a nanotechnology solution for the non-invasive detection and monitoring of diseases, such as asthma, by identifying and measuring the concentration of nitric oxide (NO) in exhaled breath. Nitric oxide is a known breath biomarker and the medical literature has published, recently, guidelines correlating the amounts of NO in breath with various airway diseases. A scalable process (flame spray pyrolysis) was employed to form nanoparticles of the NO-gas selective □-WO3. A wireless prototype of a portable, handheld breathalyzer utilizing resistive sensors based on these nanomaterials was also designed. Single exhale measurements of NO were obtained with this breathalyzer prototype. This technology is expected to become an inexpensive and affordable personalized medical diagnostic tool in the near future.