Comparisons of Fit Factors Between Two Quantitative Fit Testers (PortaCount vs. MT).

This study evaluated the consistency between two quantitative fit test devices with different methods of ambient aerosol counting. Three types of respirators (N95, half mask, and full facepiece) were worn by 50 participants (male, n = 25; female, n = 25), PortaCount (Pro+ 8038) and MT (05U) were connected to one probe to one mask, and fit factors (FFs) were measured simultaneously with the original and modified protocols. As a result of comparing MT FFs with PortaCount FFs as references and by applying for the pass/fail criteria (FF = 100), the consistency between the two devices for half masks and full facepieces was very high. N95 was somewhat weaker than the two type of respirators in the consistency; however, the correlation between the two devices was very strong (p < 0.0001). The results showed that an FF of 100 as measured by PortaCount was likely to be measured as 75 by the MT. Therefore, when performing the fit test for N95 using the MT and pass level of FF 100, a certain level of adjustment is necessary, whether end-user or putting a scaling factor by manufacturer.

Selection Guide to Wearing Respirators According to Work Situations and On-site Applicability.

BACKGROUND: This study aims to introduce the formulation of the regulation for the selection of respirators for accident preparedness chemicals (APCs) according to chemical workplace situations and to determine on-site applicability. METHODS: Workplaces were grouped into seven work categories, and APCs were classified into six groups to select adequate respirators. A survey was conducted to enhance the understanding of work situations and adequate respirators. The total number of subjects surveyed in 2018 was 201 managers and handlers, and that in 2019 was 91 handlers and 204 managers. RESULTS: Adequate respirators were allocated to each cell using the matrix method. The study observed an overall lack of understanding of work situations, especially in the operation of open devices, which was the highest at 32.7%. Despite its implementation in 2015, 17.6% and 25.0% of the managers and APCs handlers, respectively, were unaware of the regulations for selecting respirators. Only 70.4% of the APCs handler wore respirators in compliance with regulations. CONCLUSION: The method for selecting respirators according to work situations using the matrix method is considered reasonable. Thus, this study suggests that the development of educational contents and reinforcing education should be essential steps to increasing awareness of regulations.

Survey of awareness about hazardous chemicals of residents living near chemical plants in South Korea.

With economic growth, the use of chemicals has continually increased, resulting in an increase of chemical accidents. Chemical accidents pose a life threat and can lead to many health problems among the residents living in close proximity to chemical plants. This study aimed to investigate the awareness of the residents living near chemical plants about hazardous chemicals, as well as to survey the awareness of workers who do not directly handle chemicals at chemical plants (WNHCs). To this end, a questionnaire survey was conducted among a total of 600 residents and 160 WNHCs. The questionnaire was composed of three items: awareness of chemical risk, awareness of countermeasures in chemical accidents, and imperious necessity of PPE (personal protective equipment). Statistical analysis of the data was performed with the Statistical Package for Social Sciences (SPSS) version 18.0. The results show that the government needs to complement the notification system of chemical risk for residents who live close to chemical plants. The highest priority of PPE which residents want to prepare for chemical accidents was respiratory protective equipment (RPE). They responded that, if necessary to purchase PPE, they could bear a portion of the expenses (up to US $30). This study provides basic data for the development of programs and policies on chemical safety relevant for the residents living in close proximity to chemical plants in South Korea.

Effect of the tight fitting net on fit performance in single-use filtering facepieces for Koreans.

To get a better fit performance of filtering facepieces, a tight fitting net (TFN) was invented. This study was carried out to evaluate whether the TFN improves fit performance using a quantitative fit test (QNFT). The existing mask was of cup type with an aluminum clip on the nose bridge. The TFN mask was the same as the existing mask, but attached a TFN instead of aluminum clip. One hundred subjects (male 52, female 48) were selected to match fourfold in Korean 25-member facial size category for half-mask (KFCH). Fit factors (FFs) were measured using a QNFT by a Portacount®Pro+8038. Three QNFTs for each mask on the same subject was conducted and geometric mean FF (GMFF) was determined. The mean and median GMFFs of the TFN masks had higher than those of the existing mask (p=<0.001). The existing masks had tendency to have higher GMFFs with common facial size categories, while the TFN masks were regardless of facial size. The result indicates that putting even pressure on the entire parts of filter media would improve fit performance. In conclusion, to get a good fit when wearing filtering facepieces, a TFN would be an alternative to mask designing.

Correlation between basic physical fitness and pulmonary function in Korean children and adolescents: a cross-sectional survey.

[Purpose] The purpose of the present study was to determine whether there was a correlation between basic physical fitness and pulmonary function in Korean school students, to present an alternative method for improving their pulmonary function. [Subjects and Methods] Two hundred forty healthy students aged 6-17 years performed physical fitness tests of hand-grip strength, sit and reach, Sargent jump, single leg stance, and pulmonary function tests of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) using a Quark PFT. [Results] Muscle strength and power of boys improved in the late period of elementary school and middle school. Muscle strength of girls improved in the late period of elementary school. Analysis of factors affecting pulmonary function revealed that height, weight, BMI, and body fat significantly correlated with spirometric parameters. Right hand-grip strength, left hand-grip strength, and Sargent jump also significantly correlated with FVC and FEV1. [Conclusion] In order to improve the pulmonary function of children and adolescents, aerobic exercise and an exercise program to increase muscle strength and power is needed, and it should start in the late period of elementary school when muscle strength and power are rapidly increasing.

Development of medium-size half-mask facepiece for male workers at a shipyard and its fit performance in Korea.

Ten years ago, three differently sized half-mask facepiece prototypes were constructed from silicon using computer graphics and statistical analysis to fit them according to Korean facial dimensions. The purpose of this study was to complete the medium-size half-mask respirator based on the prototype, which would provide an adequate fit performance for male workers at a shipyard, Hyundai Samho Heavy Industry Co., in Korea. The complete respirator--the hardness 55--was manufactured with existing accessories such as a filter, exhalation valve, and strap attached. The fit performance test was conducted by performing a quantitative fit-test on 48 male subjects: workers who usually wear half-mask respirators (Dobulife Tech Co., Model DM-911, Gwangju, Gyeonggi-do, Korea). The results showed that the hardness 55 provided male subject workers with much better fit performance than the existing mask constructed by the same company. Because softness of the material of the facepiece, in particular the inner part, influenced faceseal leakage, further research on developing better-fit respirator facepieces should consider carefully the fine control of material softness.

Korea National Survey for Environmental Pollutants in the human body 2008: 1-hydroxypyrene, 2-naphthol, and cotinine in urine of the Korean population.

The Korea National Survey for Environmental Pollutants in the human body conducts representative Korean population studies, which were first initiated in 2005 in Korea. This study was conducted from 2008 to 2009 to determine the exposure levels of polycyclic aromatic hydrocarbons and nicotine in the Korean general population. The study population consisted of 4702 adult subjects from 196 sampling locations including coastal, rural, and urban areas. The urinary levels of 1-hydroxypyrene, 2-naphthol, and cotinine were measured for exposure of polycyclic aromatic hydrocarbons and nicotine. The geometric means of the urinary 1-hydroxypyrene, 2-naphthol and cotinine concentrations in the Korean general population were 0.15 µg/L (95% confidence interval (CI): 0.13-0.17), 3.84 µg/L (95% CI: 3.57-4.11) and 47.42 µg/L (95% CI: 40.52-54.32) respectively. When these values were compared with reference ranges for the United States and Germany, the levels of 1-hydroxypyrene, 2-naphthol, and cotinine were very similar for Korea and Germany, however, these levels were slightly lower in the United States. This study is the first nationwide survey of exposure to polycyclic aromatic hydrocarbons and nicotine in Korea and provides a background reference range for exposure to polycyclic aromatic hydrocarbons and nicotine in the Korean general population.

Airborne concentrations of organophosphorus pesticides in Korean pesticide manufacturing/formulation workplaces.

Pesticide manufacturing/formulation workers rather than farmers or applicators or people living with them are primarily exposed to organophosphorus pesticides (OPs). However, airborne concentrations in the workplace have rarely been determined. A total of 121 air samples (personal or area sampling) were collected at 4 factories where chlorpyrifos, EPN, parathion, and phorate, were manufactured/formulated from March through July, 2007-2008. Samples were collected by the National Institute for Occupational Safety and Health (NIOSH) method and were analyzed by GC-MS. The geometric mean (GM) level of airborne chlorpyrifos was 0.17 mg/m(3), 85% Korean Occupational Exposure Limit (KOEL) of 0.2 mg/m(3), and at 95% confidence, airborne concentrations exceeded the KOEL 58.8% of the time or less, indicating that this concentration level was unacceptable according to exposure assessment using a LogNorm2(®). However, compared with levels of TLV and/or PEL and/or WEL, the GM concentration levels of other OPs were remarkably low (range, 0.1-15.0%) and that these levels of concentrations to the other OPs were acceptable. The levels of airborne concentrations of OPs depended on isolation of the process; in other words, the levels depended on the extent to which the process was automated. The reason that the airborne concentration levels, except for those of chlorpyrifos, were very much lower than expected may be attributable to the fact that there was not exposed to 100% toxic active ingredients in pesticide formulation workplaces because of the use of supplemental agents or additives to produce complete pesticides. This study is limited since there were seldom or neither any data of previous studies to be compared with the study results nor dermal exposure data. The results were used to revise KOELs for OPs in 2010.

A survey of respirators usage for airborne chemicals in Korea.

A questionnaire survey was undertaken to identify the current status of respirator usage in manufacturing work environments subject to gas/vapor chemicals exposure in Korea and to suggest improvements to enhance the effectiveness of respirator usage. The number of target companies included 17 big companies, 110 small & mid-size companies, and 5 foreign companies, and the number of respondents included 601 workers and 69 persons in charge of respirators (PCR). The results explained clearly that respirator programs in practice were extremely poor in small & mid-sized companies. The findings indicated that the selection of respirators was not appropriate. Quarter mask including filtering facepiece was the most common facepiece form for respirator and was worn by sixty-four percent. Not a little proportion of respondents (33%) complained about the fit: faceseal leakage between the face and facepiece. A filtering facepiece with carbon fiber filter was used as a substitution for a gas/vapor respirator. Another result was that the PCR respondents' perception of the administration of respirators was very low. The results of this survey suggest that regal enforcement of respiratory protection programs should be established in Korea. On the basis of these findings, respiratory protection programs should include respirator selection, maintenance, training, and fit testing.

Evaluation of particulate filtering respirators using inward leakage (IL) or total inward leakage (TIL) testing--Korean experience.

Korean certification regulation for particulate filtering respirators requires inward leakage (IL) or total inward leakage (TIL) testing according to European Standard EN 13274-1, and the standard levels of compliance are similar to those of the European Standard. This study was conducted to evaluate particulate filtering respirators being commercially used in the Korean market using an IL or TIL test and the validity of standard level in Korea. Three half masks and 10 filtering facepieces (two top class, four 1st class and four 2nd class)-a total of 13 brand name respirators-were selected for the test with panels of 10 subjects. Each subject was classified with nine facial dimension grid squares in accordance with face length and lip length. IL or TIL testing was conducted at the laboratory of the 3M Innovation Center in which the experimental instruments and systems were established in compliance with European standards. The testing procedure followed EN 13274-1 (2001). As expected, leakages of half masks were less than those of filtering facepieces and the latter were significantly different among brands. TILs of the 1st class filtering facepieces were found to be much more than those of the 2nd class and the result may cause a wearer to get confused when selecting a mask. The main route leakage for filtering facepieces may not be the filter medium but the face seal. Therefore, it is necessary to develop well-fitting filtering facepieces for Koreans. Because leakages were significantly different for different facial dimensions, a defined test panel for IL or TIL testing according to country or race should be developed. A more precise method to demonstrate fit, for example, fit testing such as in the US regulations, will be needed before IL or TIL testing or when selecting a respirator. Another finding implies that geometric mean of five exercises for IL or TIL may be better than arithmetic mean to establish a standard individual subject mean.

Ratios of N-(2,3,4-trihydroxybutyl) valine and N-(2-hydroxy-3-butenyl) valine formed hemoglobin adducts in female mice inhalation exposure with 1,3-butadiene.

1,3-Butadiene (BD) is a known rodent and probable human carcinogen (IARC, group 2A) or 'known to be a human carcinogen' (Department of Health and Human Services, 2000). Exposure to BD can occur either via petrochemical products or through the general environment. Adducts can be used as biomarkers for biological monitoring of carcinogen exposure. This study investigated the hemoglobin adducts in blood after inhalation exposure to BD in ICR female mice for three weeks (5 h/day x 5 days/week). During the inhalation exposure, the body weights of mice were significantly lower from day 9 onward for the 500 ppm BD group and from day 4 onward for the 1000 ppm BD group. On the 1st, 2nd and 3rd weeks after inhalation exposure, the concentrations of HB Val adducts were 1.8, 3.7 and 6.2 pmol/mg globin for the 500 ppm BD group, and 5.7, 7.4 and 16.0 pmol/mg globin for the 1000 ppm BD group. The concentrations of THB Val adducts were 32.0, 42.0 and 55.0 pmol/mg globin for the 500 ppm BD group, and 67.8, 72.7 and 83.5 pmol/mg globin for the 1000 ppm BD group. Their defined ratios were higher at the earlier exposure period and at the lower concentration. They were 17.8, 11.4 and 8.87 for the 500 ppm BD group, and 11.9, 9.8 and 5.2 for the 1000 ppm BD group, on the 1st, 2nd and 3rd weeks after inhalation exposure. THB Val and HB Val adducts appear to be the important hemoglobin adducts for monitoring BD exposure, with the latter being a more predictable biomarker than the former.

Development of prototypes of half-mask facepieces for Koreans using the 3D digitizing design method: a pilot study.

In the Korean market there are several respirators for industrial purposes. Some of them are imported from global manufacturers such as 3M, and the others are developed by domestic companies. However, some of the locally made respirators have a face-seal leakage problem because they were not designed taking into account Korean facial characteristics. This pilot study was conducted to develop three face models for a half-mask based on the Korean fit-test panel and also to design three well-fitting silicon prototypes (large, medium and small) for Korean faces. For a test panel, 50 subjects were selected on the basis of lip length and face length. Shapes of faces from the test panel were scanned by a 3D scanner (Vivid 900, Minolta). The facial dimension scales for three size groups were established through statistical analysis. To ensure that the shapes fit the mean facial dimensions of each size group, similarly shaped sample faces were selected from the test panel. Mean faces with representative facial dimensions as well as face models (mannequins) were made by the Rapid Prototyper (RP; Z400, Z Corps, USA). These were reshaped to fit the mean faces by clay-modeling. The face models were digitized to recheck the fit of the facial dimensions. On the basis of the face models, three types of masks were developed through digital modeling, and tangible models were prototyped by RP. Three differently sized prototype masks were made with silicon and examined by simple naked eye test. This procedure established the mask design process based on digital technology; it can be applied for similar design projects in the future. Further study is needed to verify whether these prototypes would be a good fit for Korean faces.

Facial dimensions and predictors of fit for half-mask respirators in Koreans.

This study investigated the relationship between facial dimensions and the fit of half-mask respirators using fit factors and selected good facial dimension predictor(s) of fit for designing respirators for Korean workers. Three different brands of half-mask respirators-YS, SG, and 3M-were fit-tested on 112 men and 38 women using TSI Portacount 8020, and fit factors were determined. Before fit-testing, 10 facial dimensions were measured. Data were analyzed by descriptive statistics, Pearson's correlation analysis, and quadratic polynomial regression analysis with log-transformed fit factors (LNFF). However, some of the relationships between LNFF and facial dimensions in brand/gender subgroups were found to be curvilinear rather than linear. Because this result indicated that a multiple polynomial regression model including quadratic terms might be more appropriate than a multiple linear regression, data were also analyzed with a quadratic term by examination of the coefficient of partial correlation. No common facial dimension variables were found to be significant for all nine brand/gender subgroups, but the coefficient of regression for the linear term of the bitragion-menton arc was significant in five of nine brand/gender subgroups including male subjects of all three respirator brands. The 3M mask had the highest coefficient of determination values compared with other brands. Using the quadratic term for the 3M mask, face width (bizygomatic breadth) and nose protrusion were good predictors of half-mask fit. In four of nine brand/gender subgroups, nose protrusion was a good predictor of fit through analysis using a quadratic term. Results indicate that face width, bitragion-menton arc, and nose protrusion should be preferentially considered when designing a half-mask respirator for Korean workers.

Facial anthropometric dimensions of Koreans and their associations with fit of quarter-mask respirators.

Past studies on respirator fit or performance have mostly been done for Whites or male subjects, and little attention has been paid to minorities and Asians. To fill this gap, this study was designed to provide facial anthropometric data for Koreans and to analyze the association between facial dimensions and respirator fit factors for three brands of quarter-mask respirators, two domestic and one imported brand, using a Portacount 8020. A total of 110 university student subjects, 70 males and 40 females volunteered for participation in the study. The results of this study showed that Korean males and females have different facial dimensions as compared with those of White males and females. Unexpectedly, the imported respirator performed better than the domestic respirators. Males were found to achieve better respirator fit than females regardless of respirator brands tested. The regression analysis found no common prognostic variables with the three respirator brands studied. A stepwise logistic regression analysis was conducted to find predictive facial dimensions with respirator fits. Some facial dimensions were found to be statistically significant, but these dimensions are different from the traditionally recommended facial dimensions of face length and lip width for quarter mask. To improve respirator fit for Koreans, these different facial characteristics need to be considered in the design of quarter mask respirators.

Correlations between workplace protection factors and fit factors for filtering facepieces in the welding workplace.

Workplace protection factor (WPF) means a measure of the actual protection of respirator provided in the workplace when correctly worn. While fit factor (FF) represents a quantitative measure of the fit of a particular respirator to an individual and it is determined in the laboratory. To evaluate the relationship between WPF and FF is very important since FF may or may not be taken advantage of estimating WPF. Outside and inside Fe concentrations for three brand N95 filtering facepieces were collected on 14 workers/three respirator combinations in the welding workplace. The WPF measurements on the samples of the three respirator brands worn by 14 workers were observed to range from 2.2 to 132.9 with a geometric mean of 15.9 and a geometric standard deviation of 2.63. Respirator performances as measured by the WPF differed significantly among different respirator brands (p<0.05). In this study, correlations were found between the WPF measurements and the FF data for all samples of the three respirators (R2=0.38). The percentage of Fe particles having a smaller fraction than 1.1 microm diameter was observed as 71.6% of the total.