An acoustical landscaping study: the impact of distance between the sound source and the landscape plants on traffic noise reduction

Due to the ongoing increase in the urbanization rate, people are exposed to various environmental pollutions. One of the most threatening types of these environmental pollutions is noise pollution which has increased, especially in urban areas with the development of transportation and industries. According to the World Health Organization, after air and water pollution, noise pollution is considered to be the third most serious pollution type in metropolises. In this study, noise measurements were made on a ring road passing through an urban area and is the reason why people are exposed to noise pollution in nearby settlements. According to analysis results, it was determined that plant groups absorbed the traffic noise at different levels and as the distance between the sound source and landscape plants reduced, plants absorbed more amount of sound. In the result of test measurements, it was determined that the highest amount of noise reduction in the current situation among the selected 6 reference points was 2.8 dBA. When the distance was reduced, the measurement results detected that the mitigated sound level increased to 4.6 dBA by bringing the sound source closer to the plant groups to determine the effects of distance on sound mitigation level. In light of these research results, suggestions were made related to the planting design studies to decrease the negative effects of traffic noise.