Airborne mineral dust measurement using an integrated microfluidic device

We present a new airborne mineral dust measurement instrument consisting of a high-efficiency collection system and a microfluidic multichannel Coulter counter. Simulating a complete airborne mineral dust measurement procedure, silica microparticles are uniformly dispersed into a chamber and are subsequently collected into liquid sample of a vacuum-driven impinger; the liquid sample is then pumped to and analyzed in the multichannel Coulter counter to obtain size and concentration information. The accuracy of sizing and counting capabilities of the multichannel Coulter counter is proved by testing the mixture of standard 1.0-, 2.0- and 5.0-µm microparticles. Next, soda lime glass microparticles ranging from 2 to 10 µm, as a mineral dust simulant, are collected and analyzed. Collection efficiency is demonstrated to be 94 %. Accurate size distribution and concentration of microparticles are obtained from the multichannel Coulter counter. With its simple structure and operation, the mineral dust measurement instrument provides reliable analysis results and is promising for real-time, on-site airborne mineral dust monitoring.