The motion of pollen grains invading through the window is simulated by the computational fluid dynamics and particle-tracking calculation. Here, the simulation software CAMPAS, which is developed in Gunma University, is employed. The objectives of the present study are to estimate quantitatively indoor dispersal of pollen grains in the case of massive ventilation and effectiveness of air purifier installation for pollen removal during weak ventilation. Pollen grains are set to be invading into the room through the window, and the room has the ventilation fan on the left side wall against the window. We calculate the ratios of the number of the pollen grains fallen on the floor, and vented out from the ventilation fan to the total invading pollens through the window. It is found that a substantial fraction of pollen grains fall on the floor near the wall opposite to the window and below the ventilation fan when the air change rate per hour is 8.3. We also study pollen removal efficiency of air purifier in the case that the air change rate per hour is 1.0. The number of removed pollen grains is found to be about half of the one of fallen pollen grains. We also found that pollen grains are widely distributed due to the turbulent air flow by air purifier.

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Moth repellent (MR) is commonly used in clothing storage containers in Japan. However, the amount of MR used has not been extensively surveyed. We conducted a nationwide online survey on the indoor use of MRs in Japanese households, and used the results from 1,715 respondents to quantify the amounts and house-to-house variations. The respondents were asked how much MR, containing p-dichlorobenzene (PDCB) and pyrethroids (PYRE), was used within each dwelling, the rooms in which MR was used, together with the characteristics of the respondent's dwellings. The proportion of households using some kind of MR in the bedroom and living room was 52% and 12%, respectively. A large house-to-house variation was observed in the amount used. For all households, the mean and 95^th percentiles of the amounts of PDCB used in bedrooms were 0 and 784 g, respectively, and for PYRE 0 and 3.58 g, respectively. Amongst those households using MR, the ratio of the 95^th percentile to the mean of the amount PDCB used in bedrooms was 4.6. We identified a potentially high risk population among MR users. A significant positive correlation (r = 0.66) was observed between the amounts of PDCB used in bedrooms and living rooms, suggesting higher personal exposure for residents in houses with multi-room use. We estimated the room concentrations for PDCB and PYRE under average and extreme use scenarios, assuming a steady-state-box model. For PDCB, the ratios of estimated to measured concentrations were 0.2 for the median, and 2 for the 95^th percentile. For PYRE, the ratio was 2 for the 95^th percentile. This method will be useful in screening assessments for indoor exposure to potentially hazardous substances for which scarce measurement data exists (e.g., pyrethroids).

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The Japan Automobile Manufacturers Association (JAMA) announced its self-restraint to reduce volatile organic compounds (VOC) in the vehicle interior. Evaluation of self-restraint requires measurements in actual cars, which needs long time to obtain results. Therefore, demand exists for a measurement method that uses VOC emission factor from vehicle inner components prediction the VOC concentration in the vehicle interior. On the basis of measurements in the vehicle interior, this study focused on formaldehyde, acetaldehyde, toluene, ethyl benzene, xylene, and p-Dichlorobenzene (p-DCB) as the target VOC. Six VOC diffusion sources were then identified using the sampling-bag method. We placed the six identified inner components to be tested in bags in order to determine if the VOC concentrations were solely because of those inner components. Because aldehydes were also emitted from the vehicle paint, we excluded them from the target VOC. Thereafter, we determined the measurement conditions of the chamber (temperature, humidity, and ventilation) and measuring method of VOC emission from the backside of a specific inner component. The measurement conditions are based on the evaluation results of the chamber conditions, and JASO standard Z125 which is related to the temperature and ventilation inside a vehicle. The concentrations inside the vehicle were estimated by summing up the VOC emission factor of each of the identified inner components. The difference of measured and the predicted values, respectively, were 13% for toluene, 11% for ethyl benzene, 26% for p-DCB and Xylene predicted value were found to have a fit to measured value. The results of this work revealed that the VOC concentrations in the vehicle interior can be predicted on the basis of the amount of VOC emission factor from the identified inner components.

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This study surveyed bedrooms and bedding in 38 dwellings in Tokyo and nearby prefectures to determine the distribution of allergenic organisms (house dust mites, booklice, and fungi) in house dust and their variations among three seasons: spring, summer, and autumn. A total of 8,783 American house dust mites (Dermatophagoides farinae) were isolated from bedding and 30,927 were isolated from floors. A total of 428 European house dust mites (Dermatophagoides pteronyssinus) were isolated from bedding and 505 were isolated from floors. A similar tendency was observed in mite antigens. There was significantly more Der f 1 than Der p 1. The proportion of Japanese dwellings inhabited by D. farinae has become extremely high in recent years. A large number of booklice were also isolated: 213 from bedding and 1,628 from floors. D. farinae and booklice tended to be larger in number in summer and autumn than in spring. There were more mite antigens and fungi from floors in summer and autumn than in spring but the number of those from bedding did not significantly differ by season. Significantly fewer D. farinae and booklice were isolated from flooring than from carpets or tatami mats. Furthermore, the number of D. farinae and booklice from floors tended to decrease significantly with the frequency of cleaning the floors.
With regard to fungi, Aspergillus, Cladosporium, and yeasts were isolated frequently. Significantly more hydrophilic fungi (cfu/total dust) tended to be isolated from bedding than from floors.

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Environmental tobacco smoke (ETS) is a mixture of both gaseous and particulate matters with specific odor which affects pleasant and/or irritating sensation of human. Use of the ETS odor as a marker potentially gives a solution for evaluating a passive smoking event of non-smokers. Then, this study aimed to develop a methodology for real-time monitoring of personal exposure to ETS employing potable semiconductor monitors for odor and TVOC (Total Volatile Organic Compounds). Responses of commercially available three portable devices commercially available in Japan to the ETS were investigated in a smoker's room of an apartment house. As a reference, SPM concentrations were also measured by co-located Dust monitor. The results showed the portable monitors, except one model, successfully responded to ETS generated by smoking in indoor environment and the responses were not affected by the room mixing condition. However, the monitors were not specific to ETS; they also responded to volatile compounds originated from consumer products such as perfume and antiperspirant. Therefore, the use of gas monitor alone is not preferable for identifying exposure events to ETS. Meanwhile, one monitor, which did not respond to ETS, had sensitivity to the non-ETS gases. Even though the Dust monitor was also not specific to ETS, simultaneous responses with semiconductor monitors may help to identify the ETS-oriented signals. Therefore, the combination with different monitors may reduce false detections by separating ETS and non-ETS responses in monitoring data.

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