Noise in Cities: Urban and Transport Planning Determinants and Health in Cities

Abstract

It is a one-sided preconception that living in a city is necessarily associated with unbearable noise exposure. The observed variation of noise exposure in cities is quite large and you can find quiet residential areas as well. However, in megacities, the background sound level—“the city hum”—is usually louder due to the multitude of city sound sources. The large variation in noise levels is determined by the cumulative effect of unfavorable or thoughtful city design elements at several scales of a city’s general and neighborhood layout. This comprises several scales of planning: the transportation system, the city and building structure, population density, the design of street and building façades, the amount of green space, and the quality of the dwellings with respect to sound and vibration features. The favorable and unfavorable features differ between European, Asian, North and South American and African cities of any size and contribute to more or less health.

The estimated health effects can best be summarized by the burden of disease concept. In 2011, a WHO assessment concluded that the largest effects in terms of population spread are due to severe sleep loss and severe annoyance (each year more than one million healthy life years lost across larger agglomerations in Europe). Also cardio-vascular health (myocardial infarction, hypertension) is affected with a 5–10% higher risk for those living in noisier areas. Effects of noise on cognition and performance follow. The updated WHO reviews (2017) add further noise associated diseases (stroke, diabetes) to the list. More critical is, however, that the threshold at which severe health effects of noise occur are lowered by about 5–10 dBA. This means—if noise exposure remains at the same level of the 2011 assessment—more people are at risk. This will increase the estimated burden of disease in future assessments. However, the effects will vary widely across cities and continents.

On the preventive side, the classical approach through the reduction of levels is limited. It needs to be complemented and often fully replaced by a soundscape approach. This strategy focuses rather on sound quality, the provision of restorative space (quiet green areas) and coping options (sleeping, living on the quiet façade side). This implies an overall improvement of the environment to mitigate multisensory city stress, avoid segregation and foster supporting neighborhood relations.