Industrial Hygiene Exam 1 Practice

Fit relies on the seal between the face and the respirator, so three things determine how well it will actually seal: the geometry of the wearer's face, the respirator’s size and model being appropriate for that geometry, and how well the seal is maintained during facial movements or with facial hair. Different face shapes and sizes mean a model that fits one person tightly may leak for another, so selecting the right size or model is essential. Facial movements like talking, yawning, or chewing can break the seal and create leaks. Facial hair in the seal area—beards or heavy stubble—prevents a true skin-to-face seal, leading to poor protection even with proper donning. The other factors listed don’t affect the physical seal: color, brand, and price don’t influence fit; environmental conditions like oxygen levels, temperature, or humidity don’t determine the seal; training and procedures influence correct use but not the inherent fit of the facepiece.