Botteldooren, Dick

De Coensel, Bert

Liang, Xingyu

Sun, Kang

English

Ghent University Academic Bibliography

Evaluating the university campus soundscape:The case of Tianjin UniversityKang SunDepartment of Information Technology, Ghent University, 9000 Ghent, Belgium.Xingyu LiangState Key Laboratory of Engines, Tianjin University, 300072 Tianjin, China.Dick Botteldooren, Bert De CoenselDepartment of Information Technology, Ghent University, 9000 Ghent, Belgium.SummaryThe university campus outside environment occupies an important position in the daily life of stu-dents, providing a place to relax and restore psychologically, to study and to perform social activities.A fitting soundscape therefore contributes to the mental well-being of students and may help to fosteracademic performance. Proper ways to evaluate the quality of a university campus soundscape, tak-ing into account acoustical and perceptual aspects, are essential. This paper reports on the results ofa soundscape study performed on the Qilitai campus of Tianjin University, China. As a first step, thedistribution of sound levels over the campus was investigated on the basis of sound measurementsat various locations on the campus, during all periods of the day. Sound maps helped to delimitblack spots on the campus. As a second step, a perception study was performed among universitystudents. Individual soundwalks through the campus were carried out during which, at several loca-tions, participants had to fill in small questionnaires. The latter contained questions on sounds thatwere identified and on cognitive and affective judgments of the soundscape. Results of this survey arepresented in this paper, and suggestions for improvement of the campus soundscape are formulated.PACS no. 43.50.Rq, 43.50.Lj, 43.50.Qp1. IntroductionThe outside environment of a university campus hasa great influence on students, in particular if they areliving on campus. Previous research on the sound-scape of teaching/learning environments has mainlyfocused on the influence of indoor noise sources andtheir effects, thereby giving advice on potential im-provement of the indoor environment. For example,surveys conducted in Turkey and Brazil by Kurra [1]found that the most annoying indoor noise was causedby human activity, followed by noise from electricalequipment noise. Dockrell and Shield [2] found thatteachers and students are most affected outdoors bytraffic noise, and indoors by neighbor noise, based ona study in 142 schools in London.Research and control methodologies for indooracoustic environments have achieved some merit, andare being used widely in colleges and universities na-tionwide in China. However, up to now, relatively lit-(c) European Acoustics Associationtle attention is being paid to the outdoor acoustic en-vironment on university campus environments [3, 4].This paper reports on the results of a soundscapestudy performed on the Qilitai campus of Tianjin Uni-versity, China. Both acoustical (sound level distribu-tions) and perceptual aspects (individual soundwalkswith questionnaire survey) are taken into account.2. Methodology2.1. Overview of study areaThe Qilitai campus of Tianjin University has a trape-zoid shape with an area of about 2 km2. A mapof the campus is shown in Figure 1. The stationarytime schedule of teaching hours at the university islisted in Table I. Road traffic forms the major sourceof noise on the campus. Traffic counts at the maineastern gate of the campus show a traffic intensity ofaround 2000 vehicles over the course of the rush hourperiod. In total, 24 noise monitoring locations wereselected, based on the principle that the distance be-tween measurement locations should not be more than150 m. An overview of the measurement locations isK. Sun et al.: Tianjin University campus soundscapeEURONOISE 201531 May – 3 June, MaastrichtFigure 1. Map of the Qilitai campus of Tianjin University.Table I. Time schedule of classes at Tianjin University.Class 1 2 3 4Start 08:00 09:55 14:00 15:55End 09:35 11:30 15:35 17:30also shown in Figure 1. The western and northwest-ern parts of the campus contain housing for the fam-ily members of working staff, whereas students andteachers are mostly active in the eastern part. There-fore, the sound monitoring locations are mainly dis-tributed in the eastern area, considering that the mainusers of the campus are students and teachers.2.2. Sound level measurementsThe sound pressure level was measured at each moni-toring location simultaneously using a set of 24 JapanONO SOKKI sound level meters, which were mountedon a stand of 1.2 m height. Measurements started at6:40 am and ended at 19:40 pm, whereby the soundpressure level was recorded every 20 minutes. Hence,40 values of LAeq,20min are available, covering thesound level during a single day.2.3. SoundwalksAs the main objective of this study is to investi-gate the advantages and disadvantages of the campusdesign on the its soundscape, soundwalks were per-formed on the campus as a way to take into accountthe influence of the visual scenery on soundscape per-ception [5]. A special focus was placed on three impor-tant areas of the campus (see Figure 2): the office andteaching area (area 1), the dormitory area (area 2),and the public area (area 3). During the soundwalks,participants had to fill in 3 small questionnaires, onefor each type of area that was walked through. In to-tal, 64 participants (38 males, 26 females) performeda soundwalk, mainly students of Tianjin University,living on the campus. The soundwalk route containedthree parts, through the three different areas, shownin Figure 3. The questionnaire consisted of three sec-tions: a section with questions on sound perceptionFigure 2. Three types of areas of the campus: office andteaching (labeled 1), dormitory (labeled 2), and publicarea (all other areas).Figure 3. The route of the soundwalk.and preferences, a section with a semantic analysisof the soundscape [6], and an evaluation of the roadtraffic on campus.3. Results3.1. Sound level distributionTable II shows the measurement data (daytime and20-minute sound levels, and standard deviation of the20-minute sound level) at the 24 locations. As canbe seen on Figure 1, the measurement locations werenumbered in such a way that number differences givean estimate about the distance between locations,i.e. proximity numbering. Those monitoring locationswhich stand close to each other can be expected tohave some similarities with their neighbors. This canbe seen to some degree on Figure 4, in which the 40LAeq,20min values at each of the 24 locations are plot-ted in a three-dimensional map.K. Sun et al.: Tianjin University campus soundscapeEURONOISE 201531 May – 3 June, MaastrichtFigure 4. Time history of LAeq,20min for the 24 monitoring locations from 6:40 to 19:40.Table II. Measurement data at the 24 monitoring loca-tions. Sound levels are given in dB(A). For the area type,the options are (P) public, (D) dormitory and (T) teachingand offices.Point LAeq,day LAeq,20min Std.dev. Area type1 61.5 57.2–75.2 3.5 P2 61.5 54.6–70.1 3.2 P3 55.9 50.3–67.0 3.7 T4 51.5 47.5–57.5 2.3 T5 53.9 47.7–61.4 3.6 T6 56.4 51.2–69.4 3.6 P7 55.1 51.0–63.2 2.9 P8 61.1 55.3–71.3 3.3 P9 57.3 51.2–76.4 4.7 D10 55.2 46.3–64.5 4.3 P11 61.6 53.1–71.2 5.1 P12 62.0 55.1–72.4 4.7 P13 61.8 49.7–72.5 5.0 D14 61.0 48.1–72.1 5.2 P15 57.7 49.7–68.2 4.5 T16 52.9 48.7–62.4 2.7 P17 54.9 50.1–62.5 3.2 D18 60.3 53.5–70.0 3.8 P19 58.7 52.1–65.2 3.3 P20 56.8 49.2–67.4 4.7 P21 59.9 52.1–70.2 5.1 P22 64.3 55.6–79.1 5.5 P23 62.2 54.5–73.1 4.6 D24 63.8 52.1–80.7 6.0 DThere are four clear peaks in Figure 4, which are allabove 70 dB(A). These correspond to monitoring lo-cations 12/13 (gateways of the restaurants) and 21/22(west gate of the campus), at around 11:40 and 17:40.On the basis of Table I, it can be derived that theseare rush hours, during which students go to restau-rants to have their meals or go to the dormitories.The peaks in sound pressure level are thus associ-ated to the student activities and flows on the cam-pus. Furthermore, a number of other black points withhigh sound pressure level can be discerned from thisgraph. As can be seen on Figure 2, office and teachingareas are relatively concentrated, whereas dormitoryand public areas are relatively spread. Teaching andoffice areas generally have the lowest sound pressurelevels. The situation for public and dormitory areas isless clear; measurement locations at the western edgeof the campus are subject to the highest levels, withpeaks in LAeq,20min of more than 80 dB(A).The fourth column of Table II shows the standarddeviation of LAeq,20min at each monitoring location.Based on the Pareto principle, a threshold on the stan-dard deviation can be drawn at 5 dB(A); the 5 points(20.8% out of 24 points) with the largest standarddeviation are 11, 14, 21 (all crossroads), 22 and 24(gates of the campus). At these locations, the vari-ation in flow of vehicles and people is largest, andthese locations therefore should draw special atten-tion for soundscape management. From Figure 2, onefinds that these locations are situated mostly on theboundaries between functional areas. The time historyof LAeq,20min for this selection of monitoring locationsover the course of the day is shown in Figure 5; thepeak hours around 11:40 and 17:40 are clearly visibleon this graph.In summary, it is found that teaching and office ar-eas that are located on the boundary of areas labeled1 are subject to the highest sound pressure levels. Theconcentrated location of dormitories at the west sideK. Sun et al.: Tianjin University campus soundscapeEURONOISE 201531 May – 3 June, MaastrichtFigure 5. Time history of LAeq,20min for a selection of mon-itoring locations: 11, 14, 21, 22 and 24.of the campus may have its merits regarding cost sav-ing and ease of management, but it also results inheavy rush hour traffic of pedestrians, bikes and ve-hicles. Consequently, the west gate of the campus issubject to relatively high sound pressure levels, dueto the amount of traffic and the presence of a loudroad surface.3.2. Sound perception and preferenceThe first section of the questionnaire administered tothe participants consisted of questions on the presenceand preference of sounds. A preliminary investigationof the campus soundscape showed that there are 13main kinds of sounds, and these were subsequently in-cluded in the questionnaire. Figure 6 shows the frac-tion of participants that noted down that they hearda particular sound along each of the three differentroads of the soundwalk. Birds singing, bicycles andchatter are most heard along road 2, whereas wind,vehicle noise and whistle sounds draw more attentionalong road 3. It can be expected that, next to the ac-tual presence of sound sources, also the visual sceneryalong each of the three roads influences the attentionthat people pay to particular sounds.Figure 7 then shows the preference for each of thesounds (the order of sounds is the same in both fig-ures), as rated on a 5-point scale ranging from -2 (notfavorable) to 2 (very favorable). Clearly, the prefer-ence for particular sounds does not depend on thelocation on campus, there is a high correlation be-tween the curves for the three roads; favorability toparticular sounds is long formed and relatively stable.Only for the favorability to whistle, bicycle and mo-tion sound, there is some difference between the threeroads.3.3. Semantic differential analysisThe second part of the questionnaire consisted of asemantic differential analysis of the soundscape. TheFigure 6. Perceived probability of noticing particularsounds along the three roads.Figure 7. Preference for each of the sounds heard alongthe three roads (same sounds as in Figure 6).series of word pairs used are shown in Figure 8, to-gether with the results of the questionnaire, as ratedon a 5-point scale (-2 to 2). Although mixed in theoriginal questionnaire, the results are sorted such thatwords with a negative connotation are shown on theleft hand side in Figure 8, to facilitate visual inspec-tion of the results. Overall, it is clear that road 2 isappreciated most negatively. It is located in a dor-mitory area, and although being evaluated as quiet,bleak and turbid, which fits its purpose of rest, it isalso evaluated as being more boring and depressing.Road 3 is appreciated most positively, in line withexpectations for a public area.K. Sun et al.: Tianjin University campus soundscapeEURONOISE 201531 May – 3 June, MaastrichtFigure 8. Results of the semantic differential analysis.Table III. Result of the question on road traffic.Issue Rd. 1 Rd. 2 Rd. 3Too many roadblocks – – 0.27Too narrow road 0.04 0.50 0.09Potholes 0.11 – –Too many vehicles 0.08 0.50 0.18Too many pedestrians 0.23 – 0.09Traffic jam – – 0.05No traffic rules (pedestr.) 0.23 – 0.05No traffic rules (vehicles) 0.08 – 0.18Too many bikes 0.23 – 0.093.4. Road traffic evaluationAt the end of each questionnaire, a question targetedat the practical problems existing on campus wasasked. Participants could signal 9 of the most com-mon annoying problems, identified through a prelimi-nary investigation. The results are listed in Table III.For road 2, the problems identified are that it is toonarrow, and that there is to many heavy traffic. Forroad 1, the problems identified are mainly due to theroad being shared by pedestrians and cyclists. Forroad 3, there is a conflict between cyclists and ve-hicles. These discords reflect the general griefs of thestudents, which are (i) that the amount of traffic oncampus is too high, and (ii) that the public area onthe campus is constructed as a park, which makes thetraffic situation complex.4. Conclusions and recommendationsIn this paper, the soundscape on the Qilitai campus ofTianjin University was investigated through the com-bination of sound level measurements at 24 selectedlocations on the campus, and soundwalks among stu-dents, during which a small soundscape questionnairehad to be filled in at several locations along the walk.The distribution of sound levels over the campus wasinvestigated, taking into account three different ar-eas according to their use: teaching and office spaces,dormitories, and public areas. It was found that soundlevels are highest at the west side of the campus, andthat these high levels are mainly caused by vehicle andpedestrian traffic during rush hours (students movingfrom and to the dormitories and restaurants). Thequestionnaire results revealed which kinds of soundswere most appreciated during the soundwalks; in gen-eral, a good agreement among participants and amonglocations on the campus was found. The semantic dif-ferential part of the questionnaire clearly indicatedwhich roads were most favored by participants.Overall, the design of the campus has its benefits.To good extent, the outside acoustic environment ful-fills the expectations for a campus soundscape. Nev-ertheless, a number of suggestions can be formulatedfor improving the soundscape on the campus. Firstly,the relative concentration of teaching and office ar-eas is acceptable on a campus, but attention shouldbe paid at the design of the boundaries of these ar-eas, where there is a transition into the public area,where more noisy activities can take place. A greenbelt could serve as a buffer to lower sound levels atthe office and teaching areas. Furthermore, a decen-tralized localization of dormitory spaces could spreadrush hour traffic, and thus lower peak sound levels.Aesthetic design of the dormitory areas could also in-fluence soundscape perception. Secondly, the designof crossroads in the public area could focus on the useof bypasses, thereby accounting for the almost tidalregime of student movements. Finally, restricting roadtraffic on the campus, and installing low-noise roadsurfaces would most probably improve the campussoundscape quality.References[1] S. Kurra, M. Morimoto, Z. I. Maekawa: Transportationnoise annoyance—A simulated-environment study forroad, railway and aircraft noises, part 1, overall an-noyance. Journal of sound and vibration 200 (1999)251–278.[2] J. E. Dockrell, B. M. Shield: Acoustical barriers inclassrooms: the impact of noise on performance in theclassroom. British Educational Research Journal 32(2006) 509–525.[3] W. Su, J. Kang, H. Jin: Acoustic environment of uni-versity campuses in China. Acta Acustica united withAcustica 99 (2013) 410–420.[4] W. Jie, L. Fenghua: Discussion on campus acousticenvironment. Applied Mechanics and Materials 361–363 (2013) 476–479.[5] P. Schomer, A. L. Brown, B. De Coensel, K. Genuit, T.Gjestland, J. Y. Jeon, J. Kang, P. Newman, B. Schulte-Fortkamp, G. R. Watts: On efforts to standardize agraphical description of the soundscape concept. Proc.Internoise, Lisbon, Portugal (2010).[6] B. De Coensel, D. Botteldooren: The quiet ruralsoundscape and how to characterize it. Acta Acusticaunited with Acustica 92 (2006) 887–897.

Evaluating the university campus soundscape: the case of Tianjin University

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