AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Evaluation of Sampling Media for Use in a Nanoparticle Respiratory Deposition Sampler
LEVI MINES, Jae Hong Park, Imali Mudunkotuwa, Vicki Grassian, T. Renee Anthony, Thomas Peters, University of Iowa
Abstract Number: 604 Working Group: Control Technology
Abstract The objective of this work was to broaden the applicability of an innovative nanoparticle respiratory deposition (NRD) sampler by identifying alternate sampling media to collect and quantify multiple metals. Sampling media were identified and classified into several groups: membranes, foams, mesh screens, and granular beds. The collection efficiency by size of the sampling media was measured in triplicate for metal particles generated from a spark discharge system, using a fast mobility particle sizer (FMPS; 3091, TSI, US). Collection efficiencies were compared to the nanoparticulate matter (NPM) sampling criterion, which approximates deposition in the human respiratory system for particles smaller than 300 nm with a 50 percent collection efficiency cut-point at 40 nm and is a proposed collection criteria curve for exposure monitoring of nanoparticles. Several classes of sampling media showed promise for matching the NPM sampling criterion in both theoretical and experimental situations. Nylon, polycarbonate, and PTFE membranes did not match the NPM sampling criterion curve with constant collection efficiencies by size at 77 percent (SD 1.1), 17 percent (SD 5.3), and 78 percent (SD 4.5) respectively. Several foam sampling media exhibited the correct shape of the collection efficiency curve, and one 25-mm diameter foam stopper approximated the NPM sampling criterion with a 50 percent (SD 0.1) collection cut-point at 28 nm. Widely different sampling media (foams, mesh screens, and granular beds) can be designed to collect particles with efficiencies by size matching deposition in the human respiratory system for particles smaller than 300 nm. Investigation will continue to further evaluate sampling media at varying solidities, identify new sampling media, and evaluate the collection efficiency of layers of different classes of sampling media. Final selection of sampling media will be based on collection efficiency by size, compatibility with analytical methods, minimized metals interference, commercially availability, and cost.