Application of low-cost particulate matter sensors for air quality monitoring and exposure assessment in underground mines: A review

Exposure to mining-induced particulate matter (PM) including coal dust and diesel particulate matter (DPM) causes severe respiratory diseases such as coal workers' pneumoconiosis (CWP) and lung cancer. Limited spatiotemporal resolution of current PM monitors causes miners to be exposed to unknown PM concentrations, with increased overexposure risk. Low-cost PM sensors offer a potential solution to this challenge with their capability in characterizing PM concentrations with high spatiotemporal resolution. However, their application in underground mines has not been explored. With the aim of examining the potential application of low-cost sensors in underground mines, a critical review of the present status of PM sensor research is conducted. The working principles of present PM monitors and low-cost sensors are compared. Sensor error sources are identified, and comprehensive calibration processes are presented to correct them. Evaluation protocols are proposed to evaluate sensor performance prior to deployment, and the potential application of low-cost sensors is discussed.