A new terminal building was opened at Hanoi Noi Bai International Airport (HNBIA) in December 2014 and since then the number of flights has increased. To investigate the community response to a step change in aircraft noise exposure, socio-acoustic surveys were conducted around HNBIA once before and twice after the operation. The sample sizes in the first, second, and third surveys were 891, 1,121, and 1,287, respectively. Since the use of the two runways changed before and after the operation, the noise exposures were not monotonically increased from the first survey. Thus, the differences in Lday and Lnight between before and after the operation (Δ Lday and Δ Lnight) ranged from -9 to +5 dB and from -2 to +8 dB, respectively. In this study, listening, resting, and sleep disturbances caused by the step change were investigated. It was found that the exposure–response relationships for those activity disturbances become higher according to the increase in Δ Lday or Δ Lnight. However, although the exposure–response relationships for listening and rest disturbances were higher than that in the first survey even in the case that Lday decreased from the first survey, that for awakening was slightly lower than that for the first survey.
Road traffic noise is one of the major environmental issues in urban areas. In Japan, the road traffic noise prediction model ``ASJ RTN-Model 2013,'' which has been developed by the Research Committee in the Acoustical Society of Japan (ASJ), is used widely in environmental impact assessment. Several calculation formulas for the A-weighted sound power level, LWA, of each type of road vehicle are specified in this model. Among them, the formulas for LWA of road vehicles on dense asphalt pavement have been derived using the measurement data acquired in 1991–1998. In this study, to improve the accuracy of LWA for dense asphalt pavement, pass-by noise measurements were performed on 40 actual roads during the last decade. The results revealed that LWA of passenger cars, including hybrid vehicles and mini-sized vehicles, was 1.1 dB lower than that adopted in ASJ RTN-Model 2013. Regarding the other vehicle types such as large-sized vehicles, the differences between LWA obtained from field measurements and those in the model were 0.5 dB or less, and no marked changes in LWA were found.
Two laboratory experiments were conducted to investigate the combined effect of Shinkansen (high-speed) railway noise and vibration on daily life. In Experiment 1, stimuli noise and vibration recorded outdoors were used, and in Experiment 2, those recorded indoors were used. Twenty participants were exposed to 18 stimuli comprising 9 pairs of noise and vibration in Experiment 1, whereas 20 different participants were exposed to 22 stimuli comprising 11 such pairs in Experiment 2. The results indicated that there was significant activity disturbance from the combined effect of noise and vibration; however, the influence of vibration stimuli at 65 dB or less did not disturb reading.
The road traffic noise prediction model ``ASJ RTN-Model 2013,'' which has been developed by the Research Committee in the Acoustical Society of Japan (ASJ), includes an energy-based calculation method of tunnel portal noise. In the method, tunnel portal noise is simply modeled as the sum of direct sound from vehicle sound sources and diffused sound radiated from the tunnel portal. To calculate the diffused sound, point sources are distributed on the portal, and the point sources are assumed to be omnidirectional. ASJ RTN-Model 2018 follows the basic concept of the calculation method, and the diffused sound component has been revised so the point sources have adequate directivities. In this study, such a calculation method was validated by a field experiment using a ``split bamboo type'' tunnel and a test vehicle as a sound source. As a result, it was found that calculation results considerably varied depending on the treatment of the diffused sound component directivity, the positions of the point sources for the diffused sound component, and the diffraction over an oblique tunnel edge, and that the newly introduced calculation setting of the directional sources is the most accurate. The new calculation setting was found to have the advantages of high accuracy and simplicity of calculation.