Sensor (image) Chalmers University of Technology Share Print E-Mail Caption The new optical nano-sensor can detect low concentrations of nitrogen dioxide very precisely - down to the parts-per-billion level (ppb). The measuring technique is built upon an optical phenomenon which is called a plasmon. It arises when metal nanoparticles are illuminated and absorb light of certain wavelengths. Credit Insplorion/Johan Bodell Usage Restrictions With credit Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.