Performance test of an aerosol concentration measurement system based on quartz crystal microbalance

Abstract

QCM or quartz crystal microbalance is a well-known sensor technology that generates cycles of oscillation related to mass change on the crystal's surface. This crystal works well when it has a frequency counter and an oscillator to drive the crystal and count the oscillation, and a good airflow regulator. This study developed a measurement system for aerosol concentrations with a diameter of less than 2.5 micrometers. The system consists of QCM sensors, an oscillator, a frequency counter, and an airflow regulator. The system was tested inside an exposure chamber with a constant emission source for the different velocity speeds, namely v 1, v 2, v 3, v 4, and v 5 . The test was conducted every10seconds due to the saturated time of the QCM related to the mass loading effect of aerosol. The results show that the system can drive the QCM sensor with a frequency of 5MHz. The measurement system works well to measure aerosol concentrationafter the preload duration often seconds and every sixty seconds in which the durations are related to the optimum QCM's response at v 1 and v 2 . The optimum performance was found to be in the laminar regime, with the sample rate of 0.6 m/s to 1.0 m/s.