Evaluation of particle penetration and breathing resistance of N95 filtering face-piece respirators and uncertified dust masks

نویسندگان

  • Joel Amilcar Ramirez
  • Joel A. Ramirez
  • JOEL AMILCAR RAMIREZ
  • Thomas M. Peters
  • Matthew W. Nonnenmann
  • Nathan B. Fethke
چکیده

Evaluation of particle penetration and breathing resistance of N95 filtering face-piece respirators and uncertified dust masks. has been approved by the Examining Committee for the thesis requirement for the Doctor of Philosophy degree in Occupational and Environmental Health (Industrial Hygiene) at the December 2015 graduation. ii To family and friends, thank you for your support iii ACKNOWLEDGMENTS I would like to offer my thanks to my advisor, Patrick, for his guidance and advice. I want to thank my committee members for their time and expertise. I am very grateful to the students for their support during this endeavor. This study would not have been possible without the research training and financial support from the Heartland and Health. Finally, thanks to faculty and staff that helped me throughout the projects and education. iv ABSTRACT The research presented in this doctoral dissertation strived to increase knowledge with respect to respirators performance in the workplace by evaluating particle penetration and breathing resistance (BR) of N95 filtering face-piece respirators (FFRs) under simulated air environmental conditions, determining maximum particle penetration of uncertified dust masks (UDMs) against sodium chloride (NaCl) and BR of UDMs and FFRs when challenged against Arizona road dust (ARD), and evaluating BR of FFRs while performing power washing in swine rooms. A novel test system was used to measure particle penetration and BR of two N95 FFRs under modified environmental conditions. NaCl particle penetration through the FFR was measured before and after the BR test using a scanning mobility particle sizer. BR of the FFR was measured by mimicking inhalation and exhalation breathing, while relative humidity and temperature were modified. BR was evaluated for 120 min under cyclic flow and four temperature and relative humidity air conditions. The BR of the FFRs was found to increase significantly with increasing relative humidity and lowering temperature upstream the FFR (p < 0.001). Measured particle penetration was not influenced by the simulated air environmental conditions. Differences in BR was observed between FFRs indicating that FFRs filtering media may perform differently under high relative humidity in air. In the second study, the maximum particle penetration of five commercially available UDMs was evaluated against NaCl aerosol. Particle penetration was carried out as specified by National Institute for Occupational Safety and Health (NIOSH) to certify N95 FFRs (42 CFR Part 84). Particle penetration was found to vary between 3% and 75% v at the most penetrating particle size. …

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تاریخ انتشار 2016