Uptake Rates of PDMS-Based Passive Sampling Materials for Aerosols with Varying Particles Sizes
DONG GAO, Elizabeth Lin, Jonathan Martin, Krystal Godri Pollitt,
Yale University Abstract Number: 589
Working Group: Aerosol Exposure
AbstractPassive sampling using sorbents is an economical and versatile method of measuring air pollutants. Airborne particles can be collected onto passive samplers by gravity, impaction, and diffusion, following theories of particle deposition velocities according to particle sizes. However, the passive samplers may not effectively capture particles in all size ranges, and the uptake rate of sampling materials for aerosols with different sizes remains poorly understood, limiting their utility in quantifying exposure levels. In this study, we investigated the uptake rates of three polydimethylsiloxane (PDMS)-based passive sampling materials –PDMS foam, PDMS tubes, and XAD-coated PDMS tubes – for aerosols with varying sizes. We generated polydisperse fluorescent calibration aerosols centered on different geometric mean sizes to better simulate real-world conditions and exposed the sampling materials to these aerosols in a controlled chamber environment. Aerosol concentrations and size distributions were monitored during exposure with an optical particle counter. After exposure, the total volume of particles captured by each sampling material was quantified by measuring the collected fluorescence, and the overall uptake rate was then calculated. Our results show that the uptake rates were size-dependent and varied between the different PDMS-based passive sampling materials. The PDMS foam exhibited the highest overall uptake rate, possibly due to the enhanced surface area given its porous structure, followed by PDMS tubes and XAD-coated PDMS tubes. This study provides insights into the performance of PDMS-based materials for sampling aerosols with different sizes, which could aid in estimating levels of exposure to aerosols or aerosol constitutes using passive sampling techniques.