Many people have often reused their disposable respirator multiple times due to reasons of economy and purchasing inconvenience. However, multiple use of a disposable respirator may lead to an adverse effect of its protection performance. In this study, we aimed to determine changes in the protection performance of disposable respirators related to multiple use and to suggest the appropriate number of times of use. The masks of the brands T and Y were selected in this study, respectively. A mask of each brand was used for testing at the same time and place for two hours per day. The protection performance of each disposable mask was tested after consecutive use on days two, three, and four. The protection performance tests for each used mask following wear on a mannequin were performed in the laboratory using GRIMM’s fine dust monitoring device and TSI’s nebulizer. The concentration of PM10, PM2.5, and PM1.0 inside and outside the mask was measured. The filtration rate was calculated and the results were analyzed using the SAS statistical program. The protection rates of the brandnew masks of T and Y brands (blank test) were 80% and 60%, respectively. After one-day usage, the protection rates of the brand-new T and Y branded masks significantly decreased from 80% to 60% and from 60% to 50%, respectively. Rather, the slight drops of protection rate were observed after two or more days of respirator use. Our findings indicate that the change of protection performance could occur after one-time use. It would not be recommended to use disposable respirators several times in terms of in terms of protecting human health from environmental hazards.

This study was conducted to develop a Han-sik database as well as to assess the effects of Han-sik on dietary quality among Koreans. The Han-sik database was developed by a focus group composed of food and nutrition specialists considering the results of Han-sik perception surveys conducted in previous studies for frequently consumed dishes. Among the 1,322 dish items identified in the 4th (2007-2009) Korea National Health and Nutrition Examination Survey (KNHANES), 973 items (73.6%) were classified as Han-sik. Han-sik usage was defined as the percentage of Han-sik items of all individually consumed dish items in the dietary data of 22,113 subjects who participated in a 24-hour diet recall in the 4th (2007-2009) KNHANES. Dietary quality was evaluated based on adherence to the Korean Food Guidance System (KFGS), which was calculated as the percentage of the number of servings consumed in each food group out of recommended servings according to age and sex. Mean usage of Han-sik was 80.1% and was higher in older age groups, rural areas, as well as in households at the lowest income level. Han-sik usage was also higher on weekdays as well as for breakfast. Adherence to the KFGS was significantly higher for grains, meat · fish · egg · beans, vegetables, and fruits (p<0.001) but lower for milk · dairy products and oils · fats · sugars (p<0.001) across the quartiles of Han-sik usage. The results of this study indicate that Han-sik usage is high among Koreans. Further studies are needed to update the Han-sik database as well as investigate the association between health-related factors and Han-sik use.

Accuracy of dietary assessment depends on correct estimation of quantity as well as correct data on composition of the products. Milk and soymilk were considered quite homogeneous in items of package size and composition. One serving size of fluid milk and soymilk is considered 200 mL but there are products with different amounts on the market. This study was conducted to investigate variations of amounts and composition of fluid milk and soymilk products of one portion siz on Korean market. Twenty-nine milk products were purchased and categorized into 8 groups-regular, low-fat, skim, chocolate, strawberry-flavored, banana-flavored, and black soybean-added. Sixteen fluid soymilk products were purchased and categorized into 4 groups-regular, infant, black sesame or black soybean added and others. Actual volume of each product was measured by mass cylinder and compositions of major nutrients on the package were compared to the values in the most widely used nutrient DB in Korea. Amounts of milk specified on the package of purchased products were 182.3-318.5 ml, the largest being banana-flavored milk. Amounts of soy milk were 184.3-240.5 mL, the largest being regular soymilk. Measured amount of each products were close to the amount on the package (<5%). Contents of macronutrients on the package were different from the food composition table in several products. The amounts of calcium varied greatly among the products due to the popularity of adding calcium to milk and soymilk products recently. These variations in the amount and contents of major nutrients in milk and soymilk products can lead to considerable error to the results of dietary assessment unless the amount and the composition of each product are regularly updated in the food composition table whenever the new products are introduced in the market.