Traffic Noise and Human Living Environment

Traffic noise has become more and more serious in city ambient noise than ever. The paper presents a new method on the evaluation of city ambient noise. Road traffic noise calculation model and railway noise calculation model is given in this paper. Now the method has been testified in the evaluation in some newly built residential area in Beijing. 1 INTRODUCTION In all kinds of city ambient noise pollution sources, the traffic noise, including highway traffic noise and railway noise, is the most harmful one to residents who live at roadside. According to the statistics, among the complaint letters received by the environment protection departments of large and medium cities in China (Populations over 5 million and 1 million), the complaints to the traffic noise pollution amount to over 50% of the complaints in all of city ambient noise pollution. 2 PREDICTION MODEL AND CALCULATION Through the investigation and test of railway and traffic noise influence to the residents living environment, we have made successful prediction for the environmental noise of a residential community in Beijing, Residence A which is located at north side of a railway line, west side of the West Third Ring Road and the south side of a certain sub-artery road. The suitable prediction allowed the developers have made the noise deduction designing gained better effect latter for every apartment prior to the construction. The plan of Residence A is seen at figure 1. Firstly, we analyzed the anxiety degree of people who live in different noise environments. Based on the statistics of over 1,000 investigated persons, there is a linear interrelated linkage between the noise anxiety effect in the living environment (shown by HA%) and the environmental noise level. HA% = −412.5 + 267.3lgLA (1) By above formula, the anxiety rate to the different indoor environmental noise level can be seen in Table 1. Indoor noise level LA(dBA) 35 40 45 50 55 60 65 70 HA(%) 0.2 15.7 29.4 41.6 52.7 62.8 72.1 80.7 Table 1: The calculated date of HA and indoor noise level. At the same time, statistics were also made for people at different age under 50dBA noise environment. Their relative anxiety rate can be seen at Table 2. Copyright SFA InterNoise 2000 2 Figure 1: Residence A plan. Age <30 30 to 40 40 to 50 50 to 60 >60 HA(%) 10 20 35 50 60 Table 2: The survey date of HA of different age. By measuring the traffic noise at the various distances on the city artery and sub-artery, we have resulted the measurement at Table 3. Test position Time Leq L10 L50 L90 σ Traffic flux West third ring road (artery road) Day 71.1 72.0 67.0 56.0 6.5 5500 Night 60.5 63.0 61.0 53.5 5.8 1854 Lotus flower road (sub-artery road) Day 69.4 74.0 68.5 65.0 4.9 2493 Night 60.5 62.0 60.0 53.0 4.8 642 Table 3: The measured data of roadside noise level. We also made the measurement for the railway noise effects within the distance from 30m to 200m along the railway line. In China, the extent of applicable land is beyond 30m to the center line of rails at each side of railway. See Table 4 for the test result. Time Test point Leq L10 L50 L90 σ Day 30m from rail central line 67.2 76.5 54.0 53.0 4.8 Night 67.0 76.0 54.0 44.0 4.5 Day 60m from rail central line 64.2 73.0 51.0 50.5 4.2 Night 63.8 73.0 51.0 42.0 3.8 Day 120m from rail central line 61.1 71.0 48.0 47.0 2.6 Night 60.6 70.5 48.0 41.0 2.4 Day 200m from rail central line 58.2 68.0 46.0 42.0 2.4 Night 57.8 67.0 45.0 39.0 2.2 Table 4: The measured data of railway noise level. Copyright SFA InterNoise 2000 3 On the basis of above investigation and the test result, we have carried on the calculation on the comprehensive noise effects for Residence A. The formula 2 is the noise calculation model. This model can be divided into two parts which is called road traffic noise calculation model and railway noise calculation model. See formula 3 and formula 4 respectively. Leq (T ) = 20Lg (1/T ) [ N ∑