There is test method according to JIS A 4706:2000 for the evaluation of sound insulation of window sash, this gives only the performance for whole of sash, but not for partial sound leak which really make heavy influence on the sound insulation performance of a window sash. In this paper, leakage sound through the narrow gaps is played attention, the influences of narrow gaps that decreases sound insulation performance such as directivities, strength distributions and frequency characteristics of sound leakage are made clear by acoustical experiments using a particle velocity sensor. We expect that these data will be used to find out some method effective for the improvement on sound insulation performance of window sash.

A questionnaire study was conducted around Narita International Airport in 2003, 18 months after the opening of its second runway. The questionnaire included the 28-item General Health Questionnaire (GHQ-28), Weinstein’s noise sensitivity scale, and questions on disturbances of daily life due to aircraft noise. Multiple logistic regression analysis was applied in order to investigate the mental health effects of aircraft noise taking noise sensitivity into account. A significant dose-response relationship between the neurosis identified by the GHQ-28 and the aircraft noise was found in the sensitive group, and was not in the insensitive group. This result suggests that the adverse effects on mental health may be caused mainly in sensitive subgroups. The investigation on the relationships with the disturbances of daily life revealed a significantly high correlation between the neurosis and the disturbances during evening time (1800–2300 hours). Reduction of the evening time noise would effectively mitigate the mental health effects observed in this area.