Disturbance caused by various fluctuating single noises and combined community noises

Three experiments were conducted to investigate factors influencing the (rated) disturbance caused by various noises to subjects when they were reading: (a) comparison of disturbances from various noises at 70 dB(A) L_eq; (b) comparison of exposure-response relationships between road traffic, aircraft, and train noises; and (c) the effect of road traffic background noise on the total disturbance caused by combined noise (aircraft or train noise combined with road traffic noise). From the three experiments, the following conclusions were drawn: (1) High-level components such as peak level contributed to the disturbance, since the noise was more disturbing with the increase of peak level. (2) Although the general pattern of the exposure-response relationships for aircraft and train noises was similar, the disturbance due to road traffic noise increased with L_eq level more rapidly than for aircraft and train noise. Considering that the peak level of aircraft or train noise was always higher than that of road traffic noise at equal L_eq levels, the contribution of the high-level components to the disturbance appeared to be level-dependent. (3) The background noise level did not affect the total disturbance. Because the high-level components of combined noises were almost the same, this finding was consistent with conclusions drawn in (1) and (2).