Effect of differing facial characteristics on breathing resistance inside a respirator mask.

A group of subjects with a large range of facial characteristics was asked to breathe deeply while wearing a full facepiece respirator. The facial characteristics noted were head length, head depth, bizygomatic breadth, lip length, and Menton-Sellion length. External resistances to inhalation or exhalation were varied in each of the trials. The data collected were analyzed for possible correlation between facial characteristics and breathing resistance. Although respirator resistances were found to vary, no statistically significant correlation was found with anthropometric measurements.