Study of noise pollution and acoustic condition of the Tehran schools

Subject Areas : environmental management

Rostam Golmohammadi ¹ , Farshid ghorbani ² , Hossein Mahjoub ³ , Zohreh Daneshmehr ⁴

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Received: 2007-12-31 Accepted : 2008-06-25 Published : 2010-04-03

Keywords: Noise pollution, acoustics, classroom, Schools, Tehran,

Abstract :

Noise pollution is one of the important issues of environmental pollutant in metropolitan areas and is almost one of the hazardous agents, which causes discomfort for residents and disturbs the work efficiency. Schools are the most important areas for assessment of noise pollution, because Poor acoustical conditions in classroom directly affect to speech, perception and learning of students. The present study was conducted in Tehran city, during 2004 - 2005. In this study, 90 schools were randomly sampled. Schools consisting of primary, secondary and high school. In each school 103 parameters consist of noise characteristics and acoustic condition inside and outside of schools were measured and estimated. After the base calculation conducted of 158 data record for each sample, the research data was transferred into Excel and SPSS data sheet for statistical analysis. The results showed that the mean of Leq in classroom (in normal condition) were 71.98 ± 6.54 dB (A). The mean absorption index of internal absorbed area surface of classroom was 4.55± 2.07 sabin.m2 and the mean of the reverberation time was 3.65 ± 0.79 sec. The mean values of the transmission loss of the walls between classrooms were estimated 26.50 ± 2.37 dB and for outside were 29.72 ± 2.26 dB. Results showed that 70.6% of background noise index in classroom and 61.1% of Leq was in impermissible condition. Results also showed that 99% of street side walls and 100% of separator walls had a non efficiency to isolation of noise transmission. Analysis of the results showed that, the internal sources were the main cause of noise pollution in studied schools. Improvement acoustic reform by using of tile acoustics, control of opening in doors and windows and education for noise reduction in studied schools, and site selection and acoustic base designing for future construction were proposed.