title: [The aspiratory resistance and filtration penetration of N95 filtering-facepiece respirators used widely in China].
abstract: OBJECTIVE
  The objective of this study was to investigate the aspiratory resistance, filtration penetration and their influence factors of N95 filtering-facepiece respirators used widely in China.
  
  
  METHODS
  The total of 6 brands and 21 models of N95 filtering-facepiece respirators which are certified and big sales on the market. The aspiratory resistance and filtration efficiency filter penetration were measured while air pump ran from 10 L/min to 100 L/min using differential pressure gauge and the PortaCount, respectively.
  
  
  RESULTS
  The filtration penetrations for 2 of the 21 models were lower than 95%, and the qualified rate for all models was 90.47%. The filtration penetrations gradually decreased when ventilation flow of air pump increased. The negative correlation was observed between filtration penetration and ventilation flow (r(2) = 0.711, P < 0.05). The resistances of all 21 models of N95 respirators met the requirements of the national standard. The aspiratory resistance started to elevate with the increasing of ventilation flow, and a positive correlation between both (r(2) = 0.878, P < 0.05). Significant differences of filtration penetration and aspiratory resistance were observed among between different brands (P < 0.05) although no differences of filtration penetration existed among different models of one brand (P > 0.05). But the differences of the aspiratory resistance among different models of one brand were statistically significant (P < 0.05).
  
  
  CONCLUSIONS
  The aspiratory resistances of all N95 filtering-facepiece respirators used in this study met the requirements of the national standard. And the qualified ratio of filtration penetration of all models was higher than 90%. The influencing factors of aspiratory resistance included materials, size and ventilation flow. And influencing factors for filtration penetration were materials and ventilation flow.
authors: Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors: Xinyan
authors: X
authors: Wang
authors: Tingming
authors: T
authors: Shi
authors: Wei
authors: W
authors: Lu
authors: Shaoxian
authors: S
authors: Qin
authors: Yuewei
authors: Y
authors: Liu
authors: Ying
authors: Y
authors: Tao
authors: Hongge
authors: H
authors: Zhang
authors: Email: wchen@mails.timu.edu.cn.
authors: Weihong
authors: W
authors: Chen
mesh_terms: D000395:Air Pollutants, Occupational; D002681:China; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation*; D008397:Masks / Q000592:standards; D008422:Materials Testing; D012134:Respiratory Protective Devices / Q000592:standards*
chemical_list: D000395:Air Pollutants, Occupational