Conducting quantitative mask fit tests: application details and affecting factors

Area of Science:

• Occupational Health and Safety
• Respiratory Protection
• Industrial Hygiene

Background:

• Respirators are essential for reducing exposure to hazardous particulate matter.
• Fit testing is a critical procedure for ensuring respirators achieve their Assigned Protection Factor (APF).
• Understanding factors influencing respirator fit is crucial for effective respiratory disease protection.

Purpose of the Study:

• To evaluate the fit test passing rates of reusable half and full facepiece respirators.
• To compare the effectiveness of Condensation Nuclei Counting (CNC) and Controlled Negative Pressure (CNP) fit testing methods.
• To identify factors influencing respirator fit test performance.

Main Methods:

• A fit test was conducted on 225 participants using two types of reusable half masks and two types of full facepiece masks.
• Both Condensation Nuclei Counting (CNC) and Controlled Negative Pressure (CNP) methods were employed for fit testing.
• Participant demographics (gender, age, education, training) and specific movements were recorded.

Main Results:

• Full facepiece masks demonstrated a higher passing rate (91.6%) compared to half masks (84.7%).
• Gender was a significant factor influencing passing rates, with women potentially benefiting more from full masks.
• Talking during the test was associated with a high failure rate due to instantaneous leakages; facing forward was a key correlated action.

Conclusions:

• Full facepiece respirators, particularly for women, offer superior protection and should be prioritized.
• CNC fit testing is more practical and comprehensive than CNP, with most participants passing using CNC.
• Further research should investigate the impact of physiological characteristics like double chins on respirator fit.