AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Nanoparticle Penetration through Facepiece Respirators
YUE ZHOU, Yung-Sung Cheng, Lovelace Respiratory Research Institute
Abstract Number: 26 Working Group: Control Technology
Abstract The advances of nanotechnology have produced a diverse range of nanomaterials or “engineered nanoparticles,” including metal oxides, fullerenes, nanotubes, nanowires, and quantum dots. To prevent inhalation of nanoparticles, Respirators, including NIOSH-certified N95 and P100 particulate respirators, are recommended. However, there is no information on the behavior of engineered nanoparticles in respirators. Only preliminary laboratory tests of filtering efficiency using standard test aerosols have been reported in the literature. In this study, the performance of N95 and P100 respirators for engineered nanoparticles including TiO2, fullerenes, and carbon nanotubes (CNT) was evaluated. As a comparison, the respirator performance for NaCl particles was also conducted.
Different generation methods were used to generate test particles. CNT and TiO2 particles were generated using a laboratory vortex device, whereas fullerene particles were generated using an evaporation and condensation method. Also NaCl particles were generated using a Collison nebulizer. The experimental setup includes a test chamber, the nanoparticle generator, a manikin head, and monitoring equipment. The manikin head is placed at the bottom of the chamber with a test respirator. The manikin is equipped with a probe to sample the aerosol inside the face piece. The flow rates through the respirator were 30, 85, and 130 LPM. The 30 LPM represents inhalation during a low/moderate workload. The 85 LPM is used by NIOSH for certification test. The flow rate of 130 LPM matches the peak inspiratory flow by a cyclic flow with a mean inspiratory flow of 85 LPM. Aerosol penetration through the respirator was determined by the ratio of concentration measured inside and outside the face piece using a Wide-Range Particle Spectrometer.
Results show that the penetrations meet the NIOSH criteria for all N95 and P100 respirators when flow rate was below 85 LPM. However, when flow rate increased to 130 LPM. The penetrations were found above the NIOSH criteria in many cases. Our data also indicated that the performance of N95 and P100 respirators for nanoparticles are not as good as compared to NaCl standard test particles used for respirator certification.