Mems air-microfluidic sensor for portable monitoring of airborne particulates

Abstract

We present the design, fabrication, and experimental results of a MEMS air-microfluidic sensor for measuring the concentrations of airborne particulate matter (PM) such as tobacco smoke or diesel exhaust. Our sensor (25 mm × 21 mm × 2 mm in size) consists of an air-microfluidic circuit that separates the particles by size, then transports and deposits the selected particles onto the surface of a mass-sensitive film bulk acoustic resonator (FBAR). The rate of frequency change of the FBAR due to massloading corresponds to the particle concentration in the sampled air-volume. Our sensors exhibit a low-end detection limit of single μg/m3. The small size of our sensor, combined with high sensitivity, enables it to be used in a portable PM monitor that can record personal PM exposure levels.