AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
A Shrouded Cell with Magnetic Passive Aerosol Sampler to Determine Particle Penetration through Protective Clothing Materials
PETER JAQUES, Pengfei Gao, National Institute for Occupational Safety and Health, CDC
Abstract Number: 618 Working Group: Instrumentation and Methods
Abstract The risk of worker’s exposures to aerosol particles has increased with the increase of industrial production of engineered nano-materials. Current test methods for measuring particle penetration through protective clothing materials are based on active filtration principles (e.g., downstream vacuum), which deviate from “real world” experiences, because particle penetration is most commonly driven by upstream wind. To test this, a previously developed multidomain magnetic passive aerosol sampler housed in a shrouded cell was evaluated in a recirculation aerosol wind tunnel against paramagnetic Fe3O4 particles. Particles were collected on PVC substrate and quantified using a computer-controlled scanning electron microscope. Particle penetration levels were determined by taking the ratio of particle number collected on the substrate with a fabric to that without a fabric (control). Results for each fabric obtained by this passive method were compared to previously collected results using an automated active fractional efficiency tester (TSI 3160) that used sodium chloride particles for the challenge aerosol. Several nonwoven fabrics with different thicknesses, porosity, and air permeability were evaluated. Particle penetration levels obtained by using the active sampling method were higher than those by the passive method. The lower the air permeability, the greater the difference in measured penetration as indicated by the ratio of active:passive sampling. For example, for the fabric with the highest air permeability (0.0035 m/sec-Pa) at a face velocity of 0.3 cm/s, the difference in measured penetration levels was about 1.5 times in the most penetrating particle size range of 300 nm. However, the difference was as high as 5.5-fold for the fabric with the lowest air permeability (0.00067 m/sec-Pa). The results suggest that the active sampling method overestimated particle penetration, since it can force particles through a fabric despite low air permeability.