[Fit test and improvement of self-inhalation air-purifying dust respirator].
OBJECTIVE
To investigate the fit of self-inhalation air-purifying dust respirator for Chinese workers, to improve the respirators according to Chinese facial features and to evaluate the protective effects of improved respirators.


METHODS
Two types of self-inhalation air-purifying dust respirators (cup respirators A1 and folding respirators B1) were tested by Condensation Nuclei Counting method (CNC) in 25 representative subjects (15 males and 10 females). According to the Chinese facial features and fit factors, A1 and B1 respirators were improved. The fit tests were performed for the improved A1 and B1 respirators.


RESULTS
The fit factors ≥ 100 served as the qualified standard of self-inhalation air-purifying dust respirators. The qualified rate for cup respirator A1 was 0.0%. Its geometric mean fit factor was 20.7 (6.9 ∼ 46.9). The qualified rate for cup respirator B1 was 4.0%. Its geometric mean fit factor was 26.0 (6.8 ∼ 154.9). After improvement, the qualified rates and fit factors significantly increased. The qualified rate for cup respirator A2 was 72.0% and geometric mean fit factor was 223.5 (2.2 ∼ 5932.7). There were significantly differences between respirator A1 and A2 (χ(2) = 25.09, P < 0.05). The qualified rate for cup respirator B2 was 88.0 % and geometric mean fit factor was 429.8 (41.5 ∼ 3692.9). The significant differences (χ(2) = 32.21, P < 0.05) between B1 and B2 were found.


CONCLUSIONS
To ensure the protective effects, the self-inhalation air-purifying dust respirators were designed according to Chinese facial features. The respirator fit test must be conducted when workers choose respirators.
Huazhong University of Science and Technology, Wuhan, China.
Yan-yan
YY
Yu
Wen-juan
WJ
Cheng
Dan
D
Yu
Yi
Y
Rong
Jie
J
Ping
Lu-man
LM
Jiang
Wei-hong
WH
Chen
D004867:Equipment Design; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000517:prevention & control*; D008297:Male; D008422:Materials Testing; D016273:Occupational Exposure / Q000517:prevention & control*; D012134:Respiratory Protective Devices