Real-time Monitoring of Suspended Particulate Matter in Indoor Air: Validation and Application of a Light-scattering Sensor


Abstract

Since the 1950s, there has been growing awareness of the impact of air pollution on health. Of the many recognized air pollutants, the main preoccupation has been with suspended particulate matter PM2.5 and PM10, as both can affect human health upon inhalation. Consequently, PM monitoring is of key importance for linking indoor pollution and exposure. For this purpose, a validated instrument for monitoring PM is of pivotal importance. Portable monitors are used to monitor aerosol PM in real-time and are a faster alternative to offline gravimetric techniques. In particular, aerosol monitors have the capability to track temporal changes in aerosol mass concentration, whereas gravimetric methods provide only average values. The aim of this study was to assess the performance of DustTrak DRX Aerosol Monitors and validate their suitability for determining complex aerosols for indoor air quality measurement. Three DustTrak units were used to measure different aerosols such as ambient air, polystyrene latex spheres (PSL), and environmental tobacco smoke (ETS), and the results were compared with those obtained by the standard gravimetric method. In particular, for ETS measurements obtained with photometric calibration factor (PCF) of 0.38, bias of the DustTrak relative to the gravimetric method ranged from 2% to 15%. Moreover, the working range of the tested instruments was established with limits of detection and quantification of 5 and 15 µg m-3, respectively. Furthermore, in order to propose an alternative to the gravimetric method, validation of the DustTrak monitors for assessment of PM must be performed in accordance with standards such as ISO 17025.