A questionnaire survey was conducted to the patients in a surgical ward in a hospital. Sound pressure levels were also measured in a single room, a room for four patients, a recovery room and a nurse station. It was found that the values of LAeq, 16h (daytime) and LAeq, 8h (nighttime) in all the four rooms measured exceeded the guideline recommended by Environmental Quality Standard in Japan. Air conditioner noise in single rooms and sound of cough/sneeze/snore in rooms for four patients were the sounds which patients perceived as being most annoying. Countermeasures for improving the sound environment were proposed.
The purpose of this paper is to analyse physical characteristics of wind-induced foliage sounds for the reduction of annoyance of road traffic noise. Frequency characteristics and sound pressure level of wind-induced foliage sounds from six kinds of tree were measured. It was found that, (1) the sounds from the six trees have stable components from 100Hz to 1, 000Hz; (2) the level of high frequency components decreases according to the distance; (3) the correlation between wind velocity (10min) and LAeq, 10min of wind-induced foliage sounds is high. It was suggested the roadside planting can possibly be used for the planning of sound environment by making use of wind-induced foliage sounds.