Abstract
ABSTRACTFull facepiece respirators (FFRs) with charcoal cartridges are very common wearable devices for industrial or military purposes preventing respiratory tract, face, eyes, and mouth from hazards exposure. However, related research for performance evaluation was rare. We aimed to use a self-developed testing system investigating (1) filtration efficiency (FE) of aerosols in charcoal cartridges; (2) breakthrough time of cyclohexane in charcoal cartridges; (3) fit factors (FFs) and (4) protection factors (PFs) of FRRs. The results showed that FE of charcoal cartridges against 0.3 µm of sodium chloride (NaCl) and dioctyl phthalate (DOP) particles under 85 L min–1 were 99.93% and 99.89%, respectively, which did not meet the standard 99.97% regulated for filters such as P100 and HEPA. As for 42.5 L min–1 condition (dual canisters), the FE against NaCl (99.97%) did meet the requirement set for HEPA (99.97%); however, that against DOP (99.95%) failed to meet the standard. In addition, the breakthrough time of 3000ppm cyclohexane was 31 min under 32 L min–1, which was longer than the 30 min standard described in CNS6636 Z2023 and JIS8152. As to the results of fit test among 21 subjects, only 1 failed to meet the requirement (fit factor = 500) and the average of fit factors was 8342 ± 5892. The mean value of protection factors was 112.3 ± 54.6 while 3 users had lower PFs than the assigned protection factor (APF = 50) regulated by Occupational Safety and Health Administration (OSHA). APFs obtained for particles less than 100 nm were smaller than the APF standard regulated by OSHA, indicating APF standards may be overestimated for such particle size. Therefore, users should be aware of potential risks caused by such substances in nano-sized scale (e.g., nanoparticles or viruses) when wearing FFRs.
Highlights
Respirators, mostly for industrial, medical or military purposes, are often used to protect hazardous air pollutants that could compromise health, including dust, chemical vapors, fumes, or bioaerosols from being inhaled in human bodies through airway
The results showed that filtration efficiency (FE) of charcoal cartridges against 0.3 μm of sodium chloride (NaCl) and dioctyl phthalate (DOP) particles under 85 L min–1 were 99.93% and 99.89%, respectively, which did not meet the standard 99.97% regulated for filters such as P100 and HEPA
For National Institute for Occupational Safety and Health (NIOSH) air-purifying respirators (APRs) CBRN (NIOSH, 2004a) Standard (10ppm), the test results of charcoal cartridges against organic gas in this study could be classified as CAP2 level (30 min < breakthrough time < 45 min)
Summary
Respirators, mostly for industrial, medical or military purposes, are often used to protect hazardous air pollutants that could compromise health, including dust, chemical vapors, fumes, or bioaerosols from being inhaled in human bodies through airway. There are two major types of respirators with different functions such as air-purifying respirators (APRs) and atmosphere-supplying respirators (ASRs). ASRs supply clean breathing air directly to the user from a source other than the air surrounding the user and include supplied-air respirators (SARs) and self-contained breathing. All APRs are tight-fitting and available in four forms: mouth bit respirators, quarter masks, half facepiece respirators (HFRs), and full facepiece respirators (FFRs). In addition to the function preventing from inhaling hazardous substances, FFRs can be used to protect eyes or face from contaminations caused by irrigating or erosive substances. Several factors including odor filtration, strap adjustment, filtration of particles, and ease of breathing may affect the satisfaction levels of respirator wearers.
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