Effect of vegetation on sound fields in idealised urban open spaces

Noise pollution is a major environmental problem within the EU and during the last years vegetation was examined for its benefits in increasing health and well-being of citizens from different viewpoints, including noise control and soundscape enhancement. This work focuses on numerical simulations to investigate the effectiveness of vegetation for controlling sound fields, especially in terms of the abatement of traffic noise. Two idealised urban squares were studied, one rectangular and one octagonal. Three plant types, climbing plants (ivy), living green walls with soil substrate and plants in pots (nephrolepis exaltata), were used in this investigation, based on their measured properties in laboratory, and four aspects of the use of vegetation were evaluated: effect of the amount of vegetation, effect of changing in the scattering coefficient of vegetation, effect of vegetation in different receiver positions and effect of vegetation on different groups of receivers. Parametric studies on the determination of a line source and on the definition of sound power levels referred to traffic noise were also developed. Three simulation tools were used, namely CATT-Acoustic®, CRR (Combined Ray-tracing and Radiosity) and Odeon

Vegetation in urban streets, squares, and courtyards

One of various ways in which vegetation cover used in the greening of urban areas can help improve the health and well-being of people is in how it changes the acoustic environment. This chapter presents findings of computer simulations and scale modelling to examine and quantify the effectiveness of green roof and green wall (vertical garden) systems in reducing road traffic noise for streets, squares, and roadside courtyards. Noise reduction by sound absorption in reflected and diffracted (over roofs) sound paths is investigated. Particular attention is paid to the importance of vegetation placement relative to the receiver/listening positions. Because the soil substrate used for the vertical walls has good sound absorption properties, it also can be used for green barriers. In this chapter, the effects of a low barrier made of green wall substrate are studied for an installation on the ground and on the top of buildings surrounding a courtyard

Toolbox from the EC FP7 HOSANNA project for the reduction of road and rail traffic noise in the outdoor environment

yesThis paper offers a brief overview of innovative methods for road and rail traffic noise reduction between source and receiver. These include using new barrier designs, planting of trees, treatments of ground and road surfaces and greening of building façades and roofs using natural materials, like vegetation, soil and other substrates in combination with recycled materials and artificial elements. The abatements are assessed in terms of numerically predicted sound level reductions, perceptual effects and cost–benefit analysis. Useful reductions of noise from urban roads and tramways are predicted for 1-m-high urban noise barriers and these are increased by adding inter-lane barriers. A 3 m wide 0.3 m high lattice ground treatment, a carefully planted 15-m-wide tree belt and replacing 50 m of paved areas by grassland are predicted to give similar reductions. Tree belts are shown to be very cost-effective and combining tall barriers with a row of trees reduces the negative impact of wind. Green roofs may significantly reduce the noise at the quiet side of buildings

Possible Improvement of Acoustical Climate. Part II: Possible Solutions

In the paper, the simulation PROP5 program with the road model defined as a noise source and road surroundings model, is used to predict the efficiency of noise protecting means for the chosen building. The appropriate models of verified accuracy have been chosen by comparison of the simulation results with field measurements (Walerian et al., 2010). Here, using the pre-tested simulation program, the possibility of acoustic climate improvement has been analyzed in the ranges of practical variations of the input parameters. The road parameters: its geometry (number of lanes and their positions) and traffic structure over lanes (vehicle flow rates and their average speeds) have been taken under consideration as changeable parameters, that could be corrected to obtain acoustical climate improvement. Moreover, an acoustical screen designing has been considered. The screen efficiency has been evaluated under conditions defined by the input parameters of the road and its surroundings

Greenery systems in historical urban centres: soundscape evaluation, design acoustic proposals

European cities are fast growing and noise pollution is becoming a major environmental problem. On the other hand, not many green areas remain in cities. The innovative proposal of this contribute consists in the use of green surfaces on buildings façades to abate traffic noise. Vegetation as sustainable element has gathered an increased attention for potential benefit in enhanced well-being of citizens and also for the resulting soundscape, with sounds and also aural visual interaction, useful for biodiversity. The main aim is the reduction of road traffic noise in the city centre of European cities, characterized by historical constrained buildings. Two real case studies, a square and an urban courtyard, respectively placed in Italy and in England, have been evaluated. For each case study, in situ measurements and acoustic numerical simulations have been performed. To run simulations it has been chosen the software CATT-Acoustic; then, as results check, simulations have been repeated by using CRR (Combined Ray-tracing and Radiosity) and Odeon. Acoustic properties of vegetation had been previously analyzed in laboratory. Effectiveness of various types of vegetation and their spatial distribution on the buildings facades to reduce traffic noise have been evaluated

Possible Improvement of Acoustical Climate. Part I: Measurements and Theoretical Description

In the paper, the simulation PROP5 program is used to predict the sound level in proximity of a road with defined surroundings. The simulation involves road geometry (number of lanes and their positions) and traffic structure (vehicle flow rates and their average speeds), with equivalent omnidirectional point sources representing vehicles. In Part I of the paper, the agreement between measurement and simulation results is tested to verify the accuracy degree of the applied models of a road, as a noise source and propagation throughout surrounding space. In Part II, using the pre-tested simulation program, the possibility of acoustic climate improvement has been analyzed

Greenery systems in historical urban centres: soundscape evaluation, design acoustic proposals

European cities are fast growing and noise pollution is becoming a major environmental problem. On the other hand, not many green areas remain in cities. The innovative proposal of this contribute consists in the use of green surfaces on buildings façades to abate traffic noise. Vegetation as sustainable element has gathered an increased attention for potential benefit in enhanced well-being of citizens and also for the resulting soundscape, with sounds and also aural visual interaction, useful for biodiversity. The main aim is the reduction of road traffic noise in the city centre of European cities, characterized by historical constrained buildings. Two real case studies, a square and an urban courtyard, respectively placed in Italy and in England, have been evaluated. For each case study, in situ measurements and acoustic numerical simulations have been performed. To run simulations it has been chosen the software CATT-Acoustic; then, as results check, simulations have been repeated by using CRR (Combined Ray-tracing and Radiosity) and Odeon. Acoustic properties of vegetation had been previously analyzed in laboratory. Effectiveness of various types of vegetation and their spatial distribution on the buildings facades to reduce traffic noise have been evaluate

Effect of vegetation on sound fields in idealised urban open spaces

Noise pollution is a major environmental problem within the EU and during the last years vegetation was examined for its benefits in increasing health and well-being of citizens from different viewpoints, including noise control and soundscape enhancement. This work focuses on numerical simulations to investigate the effectiveness of vegetation for controlling sound fields, especially in terms of the abatement of traffic noise. Two idealised urban squares were studied, one rectangular and one octagonal. Three plant types, climbing plants (ivy), living green walls with soil substrate and plants in pots (nephrolepis exaltata), were used in this investigation, based on their measured properties in laboratory, and four aspects of the use of vegetation were evaluated: effect of the amount of vegetation, effect of changing in the scattering coefficient of vegetation, effect of vegetation in different receiver positions and effect of vegetation on different groups of receivers. Parametric studies on the determination of a line source and on the definition of sound power levels referred to traffic noise were also developed. Three simulation tools were used, namely CATT-Acoustic®, CRR (Combined Ray-tracing and Radiosity) and Odeon®