A study of the correlation between fine particle mass loading effect and frequency shift of a bare QCM.

Fine particles are particulate matters having a diameter less than 2.5 µm, ubiquitous in ambient air and mainly resulted from many emission sources. Several epidemiologic studies have investigated fine particles that have a relationship with an inflammatory response deep in the lung and red blood cells. For these reasons, the interest in real- time monitoring of the concentrations in the ambient air has increased. In this study, a bare quartz crystal microbalance combined by an impactor, a fine particle filter paper, and a signal conditioning circuit was used to measure the fine particle concentration based on the frequency change. This study aimed to define the correlation between mass loading and frequency shift of the crystal. The mass of fine particles was calculated by multiplying the total of fine particles concentration, emission flow-rate, and measurement time. A Kanomax Digital Dust Monitor Model 3443 was used to measure the concentration of fine particles inside an experimental chamber with a volume of 12,000 cm³ for certain measurement times. At the same time, a bare quartz crystal microbalance with a fundamental frequency of 9.9780 MHz was connected to an oscillator and frequency counter to measure the frequency shift related to the fine particle concentration fluctuation. The results showed that the frequency shift of the crystal, to the fine particle mass, in which frequency decreases corresponding to the increasing amount of particle mass. [ABSTRACT FROM AUTHOR]