Acoustic environment and its restorative potential in small urban green spaces

Abstract

Small urban green spaces (SUGS) in dense city areas have been widely demonstrated to have restorative benefits to surrounding residents. However, residents' usage and experience of SUGS were indicated to be adversely influenced by adjacent traffic noise, whilst natural sounds inside could provide restorative soundscape resources. Thus, this study investigated the acoustic quality and its restorative potential in 12 SUGS in Qingdao via field measurements and questionnaire surveys. The results show that: (1) The noise level of SUGS largely ranged in 50-60 dBA, with dominant road traffic noise. Three perceptual soundscape dimensions were identified: appreciation, diversity and dynamics. (2) Scenic SUGS featured more natural sounds, lower noise levels, and more appreciation; residential SUGS featured more human sounds and worse soundscape evaluation; and business SUGS featured higher noise levels. (3) The acoustic environments in scenic SUGS showed much more restorative potential than residential and business ones, and the restorative potential of SUGS was highly influenced by sound levels (LAeq, L10, and L90), sound sources (traffic noise and natural sounds), and soundscape qualities (appreciation and diversity). The findings were expected to provide references for the sustainable planning and design of small urban green spaces in dense cities.