Suitability of wearing particulate matter protective masks in tunnel construction workers and related influencing factors

Objective To analyze the association between the suitability of particulate matter protective masks worn by tunnel construction workers and the head and face dimensions of the workers, and to investigate related influencing factors.

Methods A total of 200 workers from a tunnel construction site were selected as subjects. Basic personal information was obtained, and their body height and weight were measured. TSI Pro+8038 and 8048 were used to conduct the suitability test of the folding and cup masks, and the three-dimensional scanner Artec EVA was used for the measurement of head and face dimensions.

Results For the suitability test, the univariate analysis showed a significant difference in pass rate between the type of mask and the ethnicity of the subjects (P < 0.05). Measurements of the head and face dimensions showed that there were significant differences between the pass group and the failure group in minimum forehead size of 9501V+ masks, bitragion breadth of 9502V+ masks, bitragion-submandibular arc, bigonial breadth, nasal breadth, and BMI for 8576 masks, and transversal arc, bitragion-ophryon arc, bitragion-gnathion arc, neck circumference, morphological facial length, and BMI for 8577 masks (P < 0.05). The multivariate analysis of suitability test showed that the values of morphological facial length, nasal breadth, and BMI were positively correlated with the probability of passing the suitability test, while the value of mouth breadth was negatively correlated with the probability of passing the test. Compared with folding masks, cup masks had a higher probability of passing the test. The overall coverage of the head and face size sub-column was 85.0%, with a higher number of passes for #5, #7, #8, and #10 for folding and cup masks.

Conclusion Cup masks are more suitable for tunnel construction workers than folding masks. Higher values of morphological facial length, nasal breadth, and BMI and a lower value of mouth breadth are associated with a higher probability of passing the suitability test. With reference to the head and face size sub-column standard in China, morphological facial length can be used as the main judgment basis for rapid selection of masks, and nasal breadth, mouth breadth, and BMI can be used as the main reference bases for suitability test. In order to improve the effect of respiratory prevention, the suitability test is recommended for use to identify suitable mask types for workers.