Definition - What does Breathing Zone mean?
The breathing zone is the area immediately surrounding a worker's nose and mouth where the majority of air is drawn into their lungs. This zone is the area monitored during an industrial hygiene survey to aide in determining the presence of airborne contaminants.
Safeopedia explains Breathing Zone
The breathing zone is an important area for personal monitoring of airborne particulates, as one of the easiest routes of entry into a worker's body is through their nose or mouth. Some materials, such as asbestos, can linger in a worker's lungs for a lifetime and cause irreversible harm to their state of health. The 6 to 9 inches of area surrounding the nose and mouth make up the breathing zone for which a personal monitoring device can be attached and worn for a time period typically lasting anywhere from 30 minutes up to a full shift.