Explanation:
In qualitative fit testing, a gas, vapor, or aerosol test agent is introduced into an area surrounding the respirator user’s head. It is then determined if the wearer can sense the presence of these test agents by means of taste, odor, or nasal irritation. If the user is able to detect the agent, it means that the respirator is ineffective. Before a qualitative test is conducted, the user has to undergo a sensitivity test to see if s(he) can smell, taste or react to the substance/test agent.