Secondary analysis of exposure response relationships for Shinkansen super-express railway noise in Japan

Transcription

1 INTER-NOISE 16 Secondary analysis of exposure response relationships for Shinkansen super-express railway noise in Japan Shigenori YOKOSHIMA 1 ; Takashi MORIHARA 2 ; Keiji KAWAI 3 ; Takashi YANO 4 ; Atsushi OTA 5 ; Akihiro TAMURA 6 1 Kanagawa Environmental Research Center, Japan 2 Ishikawa National College of Technology, Japan 3, 4 Kumamoto University, Japan 5, 6 Yokohama National University, Japan ABSTRACT The Shinkansen super-express railway system has greatly increased its capacity; however, many residents of areas along the railways have been disturbed by noise and vibration from the trains. To preserve health and the environment, in 1975 the government issued the Environmental Quality Standards for Shinkansen Super-express Railway Noise, under which noise is evaluated by maximum-based metrics. However, more than years have passed since these standards were established, and since then, the use of energy-based metrics has been discussed. To provide basic scientific knowledge for the discussion, we performed a secondary analysis using micro datasets of exposure and community responses associated with Shinkansen railway noise. The data were obtained through seven socio-acoustic surveys conducted separately over the last years in Japan. First, we examined whether or not a maximum-based index shows consistent exposure response relationships according to frequency of train service. Next, we examined the effects of vibration on the exposure annoyance relationship associated with Shinkansen railway noise. Finally, we applied logistic regression analysis to the datasets. Adjusting vibration and demographics as confounding factors, we established representative exposure response relationships. Keywords: High-speed railway, Community response, Noise, Vibration, Synergetic effect: INTRODUCTION The Shinkansen railway system has greatly increased its transportation capacity since the opening of the Tokaido Shinkansen Line in The network of Shinkansen lines has been continuously expanded in Japan: the Hokuriku and Hokkaido Shinkansen Lines were partially opened in 15 and 16, respectively. However, noise, ground vibration, and low-frequency sound from running trains continue to annoy residents of areas along the lines. To preserve living environments and protect inhabitants health, in 1975 the Japanese government enacted the Environmental Quality Standards for Shinkansen Super-express Railway Noise; the next year, the Director of the Environmental Agency recommended that Shinkansen railway vibration countermeasures be urgently undertaken for environmental preservation. Enforcement of the environmental quality standards and recommendation has improved the noise and vibration environments along the railway; however, many inhabitants are still disturbed by the noise and vibration. Recently, Japanese environmental quality standards regarding noise have been amended. The Environmental Quality Standards for Noise, which are defined by environmental conditions related to noise in general living and roadside areas, were revised in 1999 to adopt L Aeq as the noise metric. 1 yokoshima@k-erc.pref.kanagawa.jp 2 morihara@ishikawa-nct.ac.jp 3 kkawai@kumamoto-u.ac.jp 4 yano@gpo.kumamoto-u.ac.jp 5 atota1218@gmail.com 6 atamura@ynu.ac.jp 2621

2 INTER-NOISE 16 Additionally, the Ministry of the Environment revised the Environmental Quality Standards for Aircraft Noise in 7, replacing WECPNL with L den. However, the Environmental Quality Standards for Shinkansen Super-express Railway Noise have yet to be revised. Many social surveys on community response to Shinkansen noise and vibration have been conducted. Tamura (1) indicated that Shinkansen railways were more negatively evaluated than conventional ones in areas where railway noise was a major factor in the sound environment. Yokoshima et al. (2) reported that community response to Shinkansen railway noise was more severe than that to other types of ground transportation noise. Yokoshima and Tamura (3) reviewed metrics of Shinkansen railway noise using three separate Japanese social surveys, and Yokoshima et al. (4) clarified the synergetic effect of noise on annoyance due to vibration from Shinkansen railways. Recently, Tetsuya et al. (5) and Morihara et al. (6) reported community response to Shinkansen railway noise in Kumamoto and Nagano prefectures, respectively. Residents of areas along Shinkansen railways tend to complain about not only noise but also vibration from the railways. Sato (7) and Yano (8) reported that noise annoyance was increased by vibrations. In addition, Yokoshima and Tamura (9, ) introduced a concept of combined annoyance due to noise and vibration, reporting interactive effects between noise and vibration on annoyance. Revision of noise metrics used in environmental quality standards has necessitated a reanalysis of community response to noise from Shinkansen trains. We have compiled seven original datasets from socio-acoustic surveys on community response to Shinkansen railway noise conducted over the last years; parts of the datasets have been archived into the Japanese Socio-acoustic Survey Data Archive. First, we examined whether a maximum-based index provides improved consistency in exposure-response relationships. Next, we verified the effect of vibration exposure on noise-related annoyance. Finally, adjusting for vibration exposure and demographic factors as confounding factors, we applied logistic regression analysis to the datasets to establish representative exposure response relationships. 2. SURVEY AND MEASUREMENT 2.1 Socio-acoustic Survey Table 1 outlines the social surveys analyzed in this paper. Every questionnaire survey included questions about annoyance and listening disturbance due to Shinkansen railway noise. However, the question items wording, response descriptor, and rating scale differed depending on the survey. Regarding annoyance due to Shinkansen railway noise, the ICBEN verbal scale (1. not at all, 2. slightly, 3. moderately, 4. very, and 5. extremely) was used in six of the seven surveys. For the seventh survey s descriptor, the KNG95 measured annoyance only for the two most annoying noise sources on a 4-point scale (1. bearable to 4. unbearable). When a respondent did not evaluate Shinkansen railway noise as one of the two most annoying noise sources, annoyance due to Shinkansen railway noise was allotted to the not at all bothered response. Thus, for this survey, annoyance was organized with a 5-point scale. The KNG95, NGY, and MOE surveys measured listening disturbance only for the most annoying source(s) with a 2-point scale. Therefore, following the KNG95 survey s procedure, the not at all bothered response was assessed as no prevalence of listening disturbance. Two types of questions were used to assess listening disturbance: four surveys (i.e., the KNG95, KNG1, NGY, and MOE) separated listening disturbance into TV/radio and telephone disturbances, whereas the other surveys organized both disturbances into a single item. Therefore, for the former type, we used the higher response between the assessed disturbances as the listening-disturbance response. In the above procedure, listening disturbance had been previously organized into 5-point and 2-point scales; therefore, it was necessary to rescale the responses onto a 5-point scale to make them commensurate with those on the 2-point scale. In this paper, the top two categories of the 5-point scale were categorized as a high prevalence level of listening disturbance. 2.2 Noise and Vibration Exposures Measurement of noise and ground vibration from Shinkansen railways was conducted on a site-by-site basis for each survey. For all of the included surveys except NGY, the measurements were performed after the socio-acoustic survey was completed; conversely, for NGY survey, the city government executed the measurements prior to the social survey. Ground vibration measurements were not carried out for the MOE or part of the FKO survey. 2622

3 INTER-NOISE 16 Regarding noise measurement, the maximum A-weighted and S-weighted sound pressure level (L ASmax ) and the A-weighted sound exposure level (L AE ) of the pass-by noise from Shinkansen super-express trains were measured at several points different distances from the track. At each measuring point, the authors calculated maximum-based and energy-based indices (L Amax and L dn, respectively) as noise exposures. The former was the mean energy value of the top % of measured L ASmax levels, and the latter was the mean energy value of L AE per pass-by train per daytime (7: 22:) and nighttime (22: 7:). From the above results, depending on noise emission and propagation conditions, one or more distance attenuation equations was formulated for each noise index by logarithmic regression. Noise exposure to each respondent was then estimated based on the corresponding formula. Similarly, for vibration measurement, maximum vibration level in the vertical direction (L vzmax ) on the ground was measured at the same points as the noise measurements using a vibration level meter. Vibration exposure (L vmax ) was the mean value of the top % of measured L vzmax levels (re 5 m/s2). Vibration exposure to each respondent was estimated using the same method as that for noise exposure. Here, we present the relationship of L vmax and MTVV [m/s 2 ] for Shinkansen railway vibration. Previous findings (12) indicated the approximate expression: log 5 2 MTVV Lv max 1. 8 Noise and vibration exposure values were rounded off to one decimal place in this paper. Table 1 Outline of socio-acoustic surveys Survey a KNG95 KNG1 FKO NGY MOE KMM NGN Date (FY) Prefecture Kanagawa Kanagawa Fukuoka Aichi Tokyo et al. b Kumamoto Nagano Line c TK TK SY TK TH, JE, TK, NG and SY Method d Visit - Mail Visit - Mail Visit - Mail Interview Interview Visit - Visit Mail - Mail Housing type e DH DH &AH DH DH DH & AH DH & AH DH Annoyance unbearable ICBEN ICBEN ICBEN ICBEN ICBEN ICBEN LD f 2/5-point 2-point 5-point 2-point 2-point 5-point 5-point Sample size , a: References for surveys (left right): (2, 5, 7, 3, 11, 5, 6) b: Tokyo, Saitama, Tochigi, Kanagawa, Shizuoka, Nagano, Osaka, and Fukuoka Prefectures c: TH, JE, TK, NG and SY: Tohoku, Joetsu, Tokaido, Nagano, and Sanyo Shinkansen lines, respectively. d: Mean distribution and collection methods, respectively. e: DH, AH: detached and apartment houses, respectively. f: KNG95 used 5-point and 2-point scales in FYs 1995 and 1996, respectively. 3. SOCIAL SURVEY AND EXPOSURE RESULTS 3.1 Demographic variables and exposures The analysis was carried out for all respondents with L Amax and L dn ranges of 51 8 and db, respectively, living in detached houses. Thus, the sample size was 4411 (see Figure 1). Table 2 indicates the relative frequency distributions of demographic and housing factors. The percentage of female respondents was higher than that of male respondents. Respondents aged years accounted for % 8% of the studied group. Regarding period of residence, >7 of respondents had continuously lived in the same dwelling for years. The ratio of respondents living in wooden houses was ~8% for those living in detached houses. Table 3 indicates the mean values of noise and vibration exposures by survey. The MOE survey indicated an L Amax value about 3 db higher than that shown in the other surveys. However, the other KS NG 2623

4 INTER-NOISE 16 surveys L Amax values fell within a 3-dB range (64 67 db). The L dn range of db was slightly larger than that of L Amax. Particularly, the KMM and NGN surveys indicated relatively low values for both indices; this was attributed to the fact that their train-service frequency was smaller than that of other lines. Finally, the L vmax index showed more variation than those of noise exposure. The Tokaido Shinkansen Line, as measured in the KNG95, KNG1 and NGY surveys, emitted higher levels of ground vibration than other lines. Table 2 Demographic factors Items Categories KNG95 KNG1 FKO NGY MOE KMM NGN Sex Male Female Age <3 Period of residence Housing structure <5 years < years years Wooden RC Steel frame Others 1 6% % 3 18% % 49% 5 12% 17% 29% % 1 69% 88% % % 4 5 8% 8% % 6 % 16% 32% 3 9% 62% 2 7% 36% % 27% 18% 12% 7% 77% 1 % % Table 3 Mean values of noise and vibration exposures Survey L Amax (db) L vmax (db) KNG KNG FKO NGY MOE KMM NGN Exposure-response relationships To express exposure response relationships, we used the percentage of highly annoyed persons (% HA) as an index of annoyance. According to the ICBEN scale, %HA was calculated from the mean percentages of extremely annoyed people (%EA) and extremely or very annoyed people (%VA). Similarly, for the annoyance scale of the KNG95 survey, %HA was calculated as the mean value of the percentages of the top two categories. Figure 1 compares the relationship between L Amax and %HA by frequency of train service. L Amax was divided at 5-dB intervals, and the frequency of train service was categorized into three groups: OV2 (>2 trains per day: Tokaido Shinkansen Line), NE1 ( 1 trains: Tohoku, Joetsu and Sanyo Shinkansen Lines), and LE1 (<1 trains: Nagano and Kyusyu Shinkansen Lines). Whereas the difference in %HA between OV2 and NE1 averaged about, LE1 averaged about 1 lower %HA than the other categories. 42% 58% 12% 18% 28% 3 6% % 8% % 62% 38% 9% 17% 3 3 % 2% % 2624

5 %LD %HA %HA INTER-NOISE 16 LE1 NE1 OV L Amax (db) Figure 1 Comparison of L Amax %HA relationships by frequency of train service Figure 2 compares the relationships between L dn (5-dB intervals) and %HA according to frequency of train service. Following Figure 1, LE1 shows the lowest %HA level. In contrast, %HA for NE1 is higher than that for OV2 at the 46 db and higher noise levels; the maximum of this difference was <%. Figures 1 and 2 show that L dn is a better index than L Amax to provide consistent exposure response relationships among train-service frequencies. 3 LE1 NE1 OV Figure 2 Comparison of L dn %HA relationships by frequency of train service For the L Amax /L dn %HA relationships, similar tendencies were observed as those shown in Figures 1 and 2. Figure 3 indicates the L dn %HA relationships. The variation of %LD for L dn was less than that for the L Amax %LD relationships, with the %LD range falling within % for all groups. LE1 NE1 OV Figure 3 Comparison of L dn %LD relationships by frequency of train service 2625

6 %HA %HA INTER-NOISE Effect of vibrations on annoyance We also assessed the effects of vibration due to Shinkansen railway noise on annoyance. Figure 3 compares the L dn %HA relationships according to vibration exposure levels. We divided the respondents into three groups: unknown, low-vibration, and high-vibration (UK, LO, and HI, respectively). Respondents to the MOE and parts of the FKO surveys, where vibration exposure was not estimated, comprise the UK group. The division between the LO and HI groups was based on relative vibration level (DL max ): the median value of the difference between L vmax and L Amax. Accordingly, the difference in %HA between UK and HI averaged ~. In contrast, %HA for HI was averaged about higher than that for LO at exposure ranges of 46 db and higher. 3 VL=UK VL=LO VL=HI Figure 4 Comparison of L dn %LD relationships by vibration 3.4 Representative exposure response relationships From the findings obtained in this paper, we establish a representative exposure response relationship for Shinkansen railway noise. In this study, a logistic regression function was used to plot the L dn %HA and L dn %LD curves. To adjust the responses, we accounted for four demographic factors as confounding factors (Table 2). In addition, the relative vibration level (DL max ) was added to the %HA curve; however, the UK group was excluded from that analysis. Figures 5 and 6 contain plots of the L dn %HA and L dn %LD curves, respectively, for 5 db intervals of L dn. Particularly, Figure 5 indicates curves for the HI and LO groups. We performed adjustments for the confounding factors of sex, age, and period of residence from results from the 5 national census. Wooden housing structure was also factored into the function. For the L dn % HA curve, at ranges of db and higher, the HI group has >% higher prevalence of %HA than the LO group. At the above three ranges, from db to db, the values of %HA in the HI group were 3, 48%, and 4, respectively. HI LO Figure 5 Comparison of L dn %HA curves by vibration exposure level using logistic regression 2626

7 %LD INTER-NOISE Figure 6 L dn %LD curve using logistic regression 4. CONCLUSIONS Noise from Shinkansen super-express railway is routinely evaluated by maximum-based metrics. However, more than years have passed since the establishment of such metrics. Therefore, the use of energy-based metrics has been discussed. To establish representative exposure-response relationships for high-speed Shinkansen trains, we performed a secondary analysis using microdata obtained in seven separate Japanese socio-acoustic surveys conducted over the last years. First, we indicated that L dn has more consistent exposure-response relationships among various frequencies of train service than L Amax. Next, we confirmed the effects of vibration on the exposure-annoyance relationship of Shinkansen railway noise, similarly to previous findings. Finally, we applied logistic regression analysis to the datasets and established representative exposure-response relationships. REFERENCES 1 Tamura A., Comparison of community response to outdoor noise in the areas along Shinkansen and ordinary railroad. ProcInterNoise94, Yokohama JAPAN, pp Yokoshima S, Tamura A. Community Response to Shinkansen Railway Noise. Proc InterNoise3, Seogwipo KOREA, pp Yokoshima S, Ota A, Tamura A. Review of metrics of Shinkansen Railway noise. Proc InterNoise9, Ottawa CANADA, pp Yokoshima S, Morihara T, Sano Y, Ota A, Tamura A. Community response to Shinkansen railway vibration, Proc InterNoise11, Osaka JAPAN, pp Tetsuya H, Murakami Y, Shimoyama K, Yano T. Comparison of community response to railway noise before and after the opening of a new Shinkansen line, Proc ICBEN14, Nara, JAPAN, 6_3. 6 Morihara T, Yokoshima S, Shimoyama K. Community response to noise and vibration caused by Nagano Shinkansen railway, Japan. Proc ICBEN14, Nara JAPAN, 6_24 7 Yano T, Morihara T, Sato T. Community Response to Shinkansen Noise and Vibration: A Survey in Areas along the Sanyo Shinkansen Line. Proc Forum Acusticum Budapest (5). 8 T. Sato, T. Yano and T. Morihara. Effects of Situational Variables on Community Response to Shinkansen Noise: A Survey in Kyushu, Japan. Proc InterNoise4, Prague CZECH REPUBLIC, pp Yokoshima S, Tamura A. Combined Annoyance due to the Shinkansen Railway Noise and Vibration. Proc InterNoise5, Rio de Janeiro BRAZIL, pp Yokoshima S, Tamura A. Interactive effects between Shinkansen railway noise and vibration on annoyance. Proc InterNoise6, Honolulu HI, pp Kaku J, Kabutoa M, Kageyama T,Kuno K, Kuwano S, Sueoka S, Tachibana H, Yamamoto K, Kamigawara K. Standardization of Social Survey Method in Japan. Proc InterNoise4, Prague CZECH REPUBLIC, pp Shimoyama K, Yokoshima S, Ota A, Morihara T, Tetsuya H, Higashijima D and Yano T. Noise and vibration analysis of the Tokaido, Sanyo, Nagano, and Kyusyu Shinkansen Line. Proc. INCE/J 14 Autumn meeting (in Japanese) pp