Investigation on Environmental Noise of a Residential Area Passed Through by Jing-hu Expressway

Objective To assess the variations of environmental noise levels before and after opening to traffic and the noise_proof effects of noise barrier, to predict the influence of the increasing volume of traffic on the environmental noise level in a certain section of Jing_hu Expressway passing through a residential area. Method The noise levels of four monitoring points such as A1 and B1, A2, A3 with a distance of 32.3 m, 68.6 m, 127 m far from the central line of expressway were measured according to the National Method for Measurement of City Environmental Noise, then the obtained data were assessed on the basis of National Standard for City Environmental Noise. Results The equivalent sound levels (LAeq) were qualified in spite of higher background value of noise in this areas. The noise levels of residential area varied irregularly in day time and increased in a certain degree in night time during the early stage after expressway opening to traffic compared with background noise level. The shorter the distance to the noise barrier was, the more significant the noise_proof efficiency was [0.03～9.08 dB(A)]. The prediction showed that the environmental noise might be over the standard without the noise barrier after 2005; Considering to the effects of the noise barrier, the noise levels of sampling points A1 and B1 32.3 m far from the expressway might be basically under the standard, at the other sampling points the noise levels might remain over the standard after 2005.Conclusion Noise barries revealed a certain noise proof efficiency. The environmental noise levels easily exceed the standard because of the higher background noise level and the additional increasing traffic noise level. So comprehensive noise control measures should be carried out to reduce the environmental noise in this area.