Tranquillity by design - Architectural and landscape interventions to improve the soundscape quality in urban areas exposed to aircraft noise

The noise emissions from aircraft negatively impact the quality of life for those in areas around airports. Excess noise levels can cause stress-related complaints, leading to adverse health effects. Although newer aircraft are significantly quieter than older models, aircraft noise pollution remains a problem. Literature suggests that the level of aircraft noise annoyance people experience is equally dependent on the level of disturbance induced by the sound and individuals’ perceived level of their own ability to cope with and control it. Traditionally, noise prediction models are used to determine the noise load around airports. If levels are deemed too high, building restrictions are put in place, and house owners are either bailed out or receive funding for acoustic insulation. However, literature on road traffic noise shows that the design of the environment that surrounds individuals has a great impact on their perception of noise annoyance. For instance, the design of buildings, streets and cities influence the propagation of sound around buildings. This can reduce or amplify the sound levels locally. Furthermore, the presence of natural features, such as trees and moving water, can evoke a more positive auditory sensation in areas exposed to traffic noise. Without changing the sound exposure levels, the sight and proximity of vegetation improves the individuals’ assessment of the soundscape quality and reduces the level of noise annoyance. Like landscapes, the perception of the acoustic environment, or soundscape, is the result of design choices. Nevertheless, the question remains as to whether the design of the built environment can yield a similar effect for aircraft noise. The doctoral research focused on this question, from both an acoustic and soundscape-perception perspective, and comprised four separate studies. The first study presents the results of a systematic in-situ measurement study, in which the sound attenuating effects of buildings exposed to aircraft noise were assessed. In the second chapter, the results from the first study were used to develop and test a method to predict the propagation of aircraft noise around buildings in a numerical acoustic model. The third study used the numerical model to compare the noise attenuation effects of building design parameters, namely height, form and cladding. The fourth chapter explored the perception of aircraft noise in urban areas with or without moving water and vegetation, using virtual-reality. Together, the four studies provide tools that can be used by architects and urban designers to improve the soundscape quality in areas affected by aircraft noise. Depending on the location and local acoustic situation, different alternatives are possible, which are supported by the results presented in this thesis.Cambridge Trust, Dutch Aerospace Centre (NLR), City of Amsterdam, City of Haarlemmermeer, Province of Noord-Hollan