What does a protection factor indicate in relation to respirators?

A protection factor indicates the level of protection that a respirator provides by comparing the concentration of contaminants in the ambient air to the concentration of contaminants inside the respirator when it is worn. This metric is essential when it comes to determining how effective a respirator is at filtering out harmful substances.

Fit testing is crucial in this context because it ensures that the respirator fits the user's face properly, allowing it to create a sufficient seal and preventing leakage. A well-fitted respirator will enhance the protection factor, ensuring that the worker is adequately shielded from airborne hazards.

The other options, while related to respirators, do not directly pertain to the protection factor. Comfort level, duration of use, and cost-effectiveness are important considerations when selecting a respirator but they do not influence the measure of protection that the respirator itself provides in terms of exposure to hazardous airborne substances. Thus, understanding the protection factor is key for assessing the safety and effectiveness of respirators in various work environments.