Abstract View
Investigation of Protection Efficiency for Masks Commonly Used for Ultrafine Particles and Their Effects on Aerosol Respiratory Deposition
JINHO LEE, Wei-Chung Su, University of Texas Health Science Center at Houston
Abstract Number: 207
Working Group: Aerosol Exposure
Abstract
Exposure to ultrafine particles has been and continues to be an essential occupational and environmental health issue. To reduce the inhalation of ultrafine particles, wearing a mask is strongly recommended. This research investigated the protection efficiency of masks commonly used to prevent ultrafine particles from entering the human respiratory tract. Besides, the change of the regional aerosol respiratory deposition in the human upper airways due to the effect of mask-wearing was also studied in this research.
The experiments were conducted in a stainless-steel test chamber. A silicone mannequin face wearing the test mask covering the mouth and nose was placed side-by-side with an identical reference mannequin face. Surrogate aerosol (NaCl particles) in the size range of 10 to 200 nm were used as the challenge ultrafine particles. Two sets of particle sizers (SMPS) were employed to measure the aerosol size distribution entered the two mannequins. For the reference mannequin, measurements were taken only at the oral cavity throughout the experiments. For the test mannequin, measurements were recorded at the oral cavity with and without masks, as well as at the outlet of the TB airways with and without masks.
The N95 mask showed an overall high protection efficiency, and the protection efficiency was 84% on average for the particle sizes studied. In contrast, the cloth mask (20%) and the mask with a breathing valve (34%) showed generally low protection efficiencies. The N95 presented a relatively more decrease in deposition friction for all particle sizes studied. The cloth mask showed a general less decrease among all masks tested.