Listening for pollution

The world’s first micro-sensor to measure air quality by ‘listening’ to the acoustic frequency of carbon dioxide has been developed by a Scandinavian consortium.

The Mascot micro-machined sensor analyses the specific resonance frequencies of gases, which change depending on the molecular mass of the gas. It has been designed to provide an early-warning system and will alert a ventilation system if oxygen levels fall too low. The acoustic resonator on the sensor’s chip can detect the signature frequency of CO2 in a volume of gas smaller than one microlitre.

The technology was developed by Norwegian and Swedish research institutes and SMEs, including Norway’s Sensonor which co-ordinated the EU-funded project.

Per Gloersen, Sensonor’s R&D co-ordinator, said that the Mascot sensor’s main benefits lay in its high-energy efficiency. He said that conventional chemical sensors are notorious for their poor long-term stability, particularly their sensitivity which, with prolonged exposure to the gas, can alter slightly over time.