If a respirator has an APF of 10, what does this mean for the user?

An APF, or Assigned Protection Factor, of 10 signifies that in a given environment, the respirator can reduce the concentration of airborne contaminants that the user inhales to one-tenth of the level present in the surrounding air. This means that if the concentration of a specific contaminant is 100 units in the environment, the user could expect to inhale no more than 10 units when wearing the respirator correctly.

This level of protection is significant but does not imply complete safety from all airborne contaminants. Users should still be aware of the limitations of the respirator and understand that the APF only provides a factor of reduction, rather than absolute safety. Therefore, while the respiration is substantially safer with an APF of 10, it does not guarantee that all contaminants are filtered out or that the user is entirely safe from exposure. This highlights the necessity for understanding the context of air quality and the importance of additional safety measures or equipment when necessary.