Comparison of Direct-reading and Gravimetric Methods of Particle Measurement in a Science Building, Silpakorn University

Abstract

This study aimed to develop relationships between particulate matter (PM) concentrations obtained from a direct-reading instrument to those from a gravimetric method. TSI DustTrak II Aerosol Monitors (Model 8530), a direct-reading instrument for PM₁₀ and PM_2.5 measurement, together with personal air pumps connected to a Sensidyne cyclone and a SKC Personal Environmental Monitor (PEM) for gravimetric PM₁₀ and PM_2.5 measurements respectively were deployed in the Faculty of Science building, Silpakorn University, Nakhon Pathom, Thailand. Comparison of the results from each instrument indicated that PM₁₀ and PM_2.5 concentrations obtained from the TSI DustTrak were higher. The linear relationship from ordinary least squares (OLS) regression between PM₁₀ data determined by TSI DustTrak (x) and Sensidyne cyclone ( ) was significant (R²=0.92) and could be represented as  = 0.272x. For PM_2.5, the relationship between concentrations determined by TSI DustTrak (x) and SKC PEM ( ) was also significant (R²=0.92) and represented by  = 4.848 . Validation of both equations was undertaken by comparing predicted values from these relationships against the actual concentrations found by gravimetric analysis, with R²=1.0 and 0.92 for PM₁₀ and PM_2.5, respectively. It is suggested that these site-specific OLS regression equations can provide fast and convenient estimation of concentrations derived by gravimetric analysis from direct-reading TSI DustTrak monitor data.