Respiratory protective equipment fit tests for researchers at the national synchrotron radiation research center

Researchers at the National Synchrotron Radiation Research Center should use respiratory protective equipment to prevent respiratory damage caused by gases, steam, solvents, chemicals, materials containing toxic substances, and oxygen-deficient environments. Those working with organic matter and certain chemical substances and those exposed to occupation dust should use respiratory protective gear to ensure their health. This study conducted qualitative and quantitative fit tests for various mask brands and sizes, namely 3M-9042, N95-9211, P95-8576, and 3M-6200 masks. The gear worn by all 18 participants in the qualitative fit test passed. By contrast, the gear worn by 12 of the 15 participants in the quantitative test passed; the failure of the remaining gear was due to differences in face shape. The N95-9211 mask can be used in three-piece protective gear because it exhibited a tight fit. Additionally, the 3M-6200 negative-pressure half-face mask exhibited the most satisfactory fit and can be used in protective gear.


Introduction
The National Synchrotron Radiation Research Center (NSRRC) is a national scientific research institution that engages in research on various substances.The materials and machinery used during the research process create dust, fibers, smoke, mist, gas, and vapor that can create biological hazards.Researchers must use respiratory protective equipment during experiments to prevent exposure to harmful substances in the air that cannot be eliminated through engineering control or administrative measures [1,2].This study conducted fit tests for respiratory protective equipment for NSRRC researchers; 3M-9042, N95-9211, P95-8576 and 3M-6200 masks were used in the tests.Each line of work at the NSRRC was analyzed to determine the hazards it entails and identify the appropriate type of protective equipment it requires.Accordingly, the fit tests were conducted by including NSRRC researchers working in the Taiwan Light Source laboratories, Taiwan Photon Source laboratories, Yanguang Building, accelerators, beam lines, instrument light building, and first and second electromechanical laboratories [3,4].

Methodology
The fit tests were conducted to determine how the respiratory protective equipment fit the researchers and to ensure its performance.Qualitative and quantitative tests were conducted.The qualitative test entailed determining the researchers' perceptions of the fit of the respiratory protective equipment, and the quantitative test entailed conducting objective scientific measurements to determine the equipment fit.

Qualitative Fit Test
The qualitative test involved olfactory sensitivity and fit tests that were conducted to determine whether the respiratory protective equipment was comfortable.Banana oil, which has a low odor threshold (approximately 0.22 ppm) and is not harmful to the human body, was used for the qualitative fit test (Table 1).

Olfactory Sensitivity Test
Various test reagents were prepared for the olfactory sensitivity test.Specifically, a stock solution (Solution A) was created by mixing 1 mL of pure banana oil with 800 mL of distilled water.Subsequently, 4 mL of Solution A was mixed with 500 mL of distilled water to yield the test reagent (Solution B).Moreover, another test reagent (Solution C) was created using 500 mL of distilled water.To perform the olfactory sensitivity test, Solutions B and C were separately added to bottles and then shaken.The separate bottles were then presented to participants, who were requested to determine each bottle's content on the basis of its smell.Only participants that could immediately determine which bottle contained the banana oil were allowed to complete the fit test.If the participants cannot immediately determine which bottle contains banana oil (B contains banana oil), they are unable to undergo the closeness test.Conversely, if they can distinguish the smell, they are eligible for the test.

Fit Test
For the fit test, the prepared test reagent containing banana oil (Solution B) was first sprayed in the air to determine the number of sprays that would engender an olfactory response in participants who were not wearing the respiratory protective equipment.The study determined that 11-20 sprays engendered an olfactory response in participants not wearing the equipment.On the basis of this finding, the study determined that more than 20 sprays must be performed for participants wearing the respiratory protective equipment.Subsequently, each participant was instructed to don respiratory protective gear as shown in Figure 1 (N95-9211), and the prepared test reagent was sprayed for more than 20 times.If the participant had no reaction to the banana oil, the fit coefficient for the respiratory protective equipment was determined to be ≥100.2), a quantitative respirator fit tester, was used to measure the concentration of particles inside and outside the respiratory protective gear [5].The concentration of particles outside the respirator was divided by the concentration of particles inside the respirator to derive the fit factor [Equation ( 1 )].Because ambient concentrations can vary over time, the fit factor was calculated by averaging the ambient concentrations before and after sampling and dividing the result by the concentration in the respirator.Both the ambient and inrespirator concentrations were determined through integration on the basis of the total number of particles quantified during the sampling periods [6,7].The fit factor was calculated using the following equation: where FF is the fit factor, CB is the ambient particle concentration before sampling, CA is the ambient particle concentration after sampling, and CR is the particle concentration in the respirator.Figure 3 depicts a photograph of the quantitative fit test setup.Figure 4 illustrates the fit factor calculated in real time by using equation (1).Participants in the quantitative fit test wore N95, P95, and negative-pressure half-masks [8].

Fit test results
The widely used 3M-9042 L and M sizes, N95-9211 L size, P95-8576 L size, and 3M-6200 mask models were used in the tests performed in this study.

Qualitative Fit Test Results
The qualitative fit test entailed spraying the prepared test reagent containing banana oil and assessing the participants' olfactory reaction to the spray.A total of 18 NSRRC researchers participated in the test.The test reagent was first sprayed in the air to determine the number of participants who would have an olfactory reaction when not wearing the respiratory protective equipment.Of the 18 participants, 11 had an olfactory reaction to the reagent when it was sprayed within 10 times.The test reagent was sprayed again in the air to determine the number of participants who would have an olfactory reaction when wearing the respiratory protective equipment.The test revealed that at least 10 participants did not have an olfactory reaction to the reagent, even when it was sprayed for more than 10 times.The corresponding fit coefficient was determined to be ≧100.Moreover, seven participants wearing the respiratory protective equipment did not have an olfactory reaction to the reagent when sprayed for more than 20 times (threshold: 11-20 sprays), and the corresponding fit coefficient was ≧100.Accordingly, all 18 participants passed the qualitative fit test.The qualitative fit test results are illustrated in Figure 5.

Quantitative Fit Test Results
The quantitative fit test results are presented in Figure 6.Fifteen NSRRC researchers participated in the quantitative fit test.The fit factors derived for the respiratory protective equipment worn by 12 of these participants were ≥100, indicating that the equipment passed the test.Three participants used 3M6200, a negative-pressure half-mask; the fit factors derived for this mask were significantly higher than those observed for the equipment worn by the other participants (as indicated by charts a, b, and c in Figure 6), indicating satisfactory fit.The equipment worn by 3 of the 15 participants (as indicated by charts l, m, and n in Figure 6) failed the fit test because the corresponding fit factors were <100.In contrast to the qualitative fit test, some failures were noted in the quantitative fit test.Possible explanations for the difference between the quantitative and qualitative fit test results are outlined as follows: First, the participants in the qualitative fit test wore N95 or P95 respiratory protective gear.According to the US Occupational Safety and Health Administration, this type of gear can filter 95% of oily and nonoily pollutants.Therefore, the gear blocked most of the banana oil solution, even when the solution was sprayed directly in front of the particpant wearing the gear.Second, the participants in the quantitative fit test wore N95, P95, and negative-pressure half-masks.The masks failed in some of the participants because the masks may have not fit well because of differences in face shape among the participants or because the masks may not have been fully compressed owing to the pressure strip above the bridge of the nose.The masks also became loose when the participants bent over or nodded their heads up and down.Moreover, the quantitative respirator fit tester detects the concentration of pollutants outside and inside the respiratory protective gear simultaneously.Therefore, it can provide more accurate measurements than do qualitative assessments.

Conclusions
This study conducted respiratory protective gear fit tests for NSRRC researchers.The test results reveal that most NSRRC researchers wore respiratory protective gear appropriately.Only a few researchers did not wear such gear appropriately because of mismatches between the gear and their facial structures.Specifically, the large and medium 3M-9042 masks did not pass the quantitative test when worn by some of the researchers for whom the masks required adjustment or replacement.Because the P95-8576 mask is bowl shaped, it could not fit every face shape.The N95-9211 mask can be used in three-piece protective gear because of its tight fit.The 3M-6200 negative-pressure half-mask exhibited the most satisfactory fit and can also be used in protective gear.To ensure that researchers have a thorough understanding of the use and management of respiratory protective equipment, education and training include explanations of hazardous substances or hazardous situations during the work process; the selection of protective equipment; methods for using, maintaining, and repairing protective equipment; the purpose and procedure of fit testing; and relevant management regulations.Respiratory protective equipment use and management education and training must be conducted at least once a year.

Figure 4 .
Figure 4. Fit factor in real time.