​Air quality monitoring systems generally include sensors designed specifically to detect fine particles. Conventional optical sensors detect particles of a given size or larger. μPMSense, the new sensor developed by CEA-Leti, can not only detect much smaller particles, it can also count and classify them.

What makes CEA-Leti’s sensor unique is its CMOS imager, which is perforated to allow a flow of air generated by a miniaturized fan coupled to the imager to be guided to the sensitive element through a fluidic channel where a laser illuminates the flow of particles. The light diffracted by any particles present in the channel is picked up by the imager. The spectral signature generated is analyzed and translated into data that can be used to count the particles and classify them by size and type.

The components—imager, fan, and laser—are integrated into a device that measures around 1 cm3 and that can detect particles under 0.3 microns in diameter. The device is compliant with today’s air-quality standards, which require the detection of particles larger than 10 microns. It is also sensitive enough be able to accommodate regulatory changes down the road. Coming very soon: a sensor that can detect tiny particles small enough to enter the lungs, which is expected to become the future standard.