[Bedroom thermal environment in Nagoya, Japan].

OBJECTIVES: The objective of this study was to estimate the indoor thermal environment and the air-conditioning pattern in bedrooms during sleeping time, and to evaluate the relationship between the indoor thermal environment and the dwelling characteristics in Nagoya, Japan. METHODS: Temperature, relative humidity and information on dwelling characteristics were obtained from 84 dwellings in summer and 100 dwellings in winter from 1995 to 2001. RESULTS: The mean percentage of bedrooms air-conditioned during sleeping time was 23% when cooled in summer and 7% when heated in winter. The mean temperature and relative humidity in bedrooms during sleeping time was 27.7 degrees C and 62% in summer, and 13.1 degrees C and 61% in winter, respectively. The temperatures in bedrooms during sleeping time were found to comply with the recommended values for an indoor thermal environment (24-28 degrees C in summer and 15-21 degrees C in winter) in 39% of the dwellings in summer and 24% of them in winter. The mean temperature in bedrooms during sleeping time was significantly higher in apartments than in separate houses (p < 0.01) in winter, although there was no significant difference of mean temperature between apartments and houses in summer. There was no significant difference in mean relative humidity between apartments and houses in both summer and winter. CONCLUSION: Although the mean temperature in bedrooms during sleeping time varied widely depending on the type of dwelling, there also appeared to be differences between apartments and houses with respect to the temperature in bedrooms during sleeping time in winter.

[Airborne concentrations of fungal and indoor air pollutants in dwellings in Nagoya, Japan].

PURPOSE: The purpose of this study was to determine airborne fungal concentrations in dwellings and to evaluate the relationship between indoor air concentrations of fungi and those of indoor air pollutants, temperature and relative humidity. METHODS: Indoor and outdoor concentrations of total fungi, xerophiles (xerophilic fungi), indoor air pollutants such as formaldehyde, nitrogen dioxide, carbon dioxide, carbon monoxide, temperature and relative humidity were measured in 54 dwellings in Nagoya, Japan. This study was performed in summer and winter from 1995 to 1998. The airborne fungal concentrations were analyzed using a pinhole air sampler and dichloran 18% glycerol agar (DG18), and compared with the levels assessed with potato dextrose agar (PDA). RESULTS: 1. DG18 can be recommended as an excellent medium for determining viable fungi concentrations in indoor air. 2. In indoor air, geometric means of total fungal and xerophile concentrations in summer were 237-301 CFU/m3 and 24.1-26.8 CFU/m3, as compared to 78.7-87.5 CFU/m3 and 18.2-29.5 CFU/m3, respectively, in winter. In outdoor air, geometric means of total fungal and xerophile concentrations in summer were 208 CFU/m3 and 9.2 CFU/m3, and 72.7 CFU/m3 and 10.1 CFU/m3, respectively, in winter. 3. The predominant genera in indoor and outdoor air were Cladosporium spp., followed by Penicillium spp. and Aspergillus spp. The major Aspergillus spp. was A. restrictus. 4. Indoor as well as outdoor air concentrations of total fungi were significantly higher in summer than in winter (P < 0.01), whereas differences in total fungal concentrations between indoor and outdoor air were not. Airborne xerophile concentrations in summer and winter were significantly higher in indoor air than in outdoor air (P < 0.01), while indoor as well as outdoor air xerophile concentrations in summer were similar to those in winter. 5. The total fungal and xerophile concentrations were not dependent on dwelling factors such as the type of dwellings, the type of flooring materials and the use of air-conditioners and/or heaters. 6. The total fungal and xerophile concentrations were not significantly correlated with the concentrations of all the indoor air pollutants. In winter, the total fungal and xerophile concentrations significantly increased in proportion to the average relative humidity (P < 0.01). CONCLUSION: The total fungal concentrations in indoor air were significantly correlated with those in outdoor air, while xerophile concentrations were not. The indoor air concentrations of total fungi and xerophiles were not dependent on those of indoor air pollutants.

[Determination of organotin compounds in polyvinyl chloride toys].

Organotin compounds in polyvinyl chloride toys were determined by GC/MS after ethyl derivatization with sodium tetraethylborate. The samples were 12 balls, 12 soft toys, 10 food toys and 13 face masks for children. Monooctyltin, dioctyltin and trioctyltin compounds were found in all face masks at the levels of 74.8-917 micrograms/g. 474-3,960 micrograms/g and 1.0-213 micrograms/g, respectively. They also were detected in 6 balls, 4 soft toys and 1 food toy. Monomethyltin and dimethyltin compounds were found in 8 face masks at the levels of 40.9-227 micrograms/g and 222-1,450 micrograms/g, respectively. Monobutyltin and dibutyltin (DBT) compounds were found in 1 ball, 3 food toys and 5 face masks. In particular, 1 ball and 4 face masks contained toxic DBT at the levels of 527-999 micrograms/g.

[Studies on the analytical method for epichlorohydrin from internal can coatings].

An improved migration test was developed for determination of trace amounts of epichlorohydrin from internal can coatings. Eight kinds of sample cans, coated mainly with epoxy resin, for foods and beverages were prepared, and both their bodies and lids were tested for migration as follows. A body was filled with n-pentane and soaked for 2 hours at 25 degrees C. A lid was soaked in n-pentane (2 mL/cm2) for 2 hours at 25 degrees C. The test solution was analyzed by GC-FID and GC/MS using two DB-WAX capillary columns with different inside diameters. The limits of quantitation were 0.05 microgram/mL by GC-FID and 0.02 microgram/mL by GC/MS with selected ion monitoring. Recoveries of spiked epichlorohydrin were 99.9-104.5% at the level of 0.05 microgram/mL and 0.5 microgram/mL, with high precision. In this study, no epichlorohydrin was found to have migrated from any of the bodies and lids.

[Determination of organotin compounds in plastic products by GC/MS after ethyl derivatization with sodium tetraethylborate].

A simultaneous determination method for 9 organotin compounds in polyvinyl chloride (PVC) and silicone products used as kitchen utensils and food packages was developed using ethyl derivatization with sodium tetraethylborate (NaBEt4). Organotin compounds were extracted with acetone-hexane (3:7) from the samples after acidification and the extract was filtered and concentrated at under 40 degrees C. After centrifugal separation, these compounds were derivatized with 2% NaBEt4 solution and determined by GC/MS. This method was applicable for simple routine analysis. Recoveries of spiked compounds were 49.1-118.1% for 3 PVC products and 88.8-102.2% for a siliconized paper. Monooctyltin, dioctyltin and trioctyltin compounds were found in all PVC food containers at the levels of 123-1,380 micrograms/g, 1,770-13,200 micrograms/g and 6.6-139 micrograms/g, respectively. They also were found in 3 gloves, 5 spouts, 1 hose and 5 pipes. Some PVC products contained monomethyltin, dimethyltin, trimethyltin, monobutyltin and dibutyltin compounds at the levels of 97.3-433 micrograms/g, 96.5-5,120 micrograms/g, 8.5-24.9 micrograms/g, 1.2-852 micrograms/g and 1.2-29.4 micrograms/g, respectively.