Spatial analysis and temporal trend of registered noise complaints in the city of Milan, Italy

Noise complaints, expressed by individuals or a group of people, are the outcome of a complex behaviour depending not only on the noise exposure and its evoked annoyance, but also on other factors such as socio-economic ones. Noise annoyance has significant impacts on the quality of life and health of inhabitants, as well as social cohesion. Thus, noise complaints are a very important issue to tackle for national and local policy makers and for all stakeholders involved in planning and management of noise mitigation actions. Within the above framework, the present study describes the analysis of noise complaints submitted by citizens to the municipality of Milan, Italy, from years 2000 to 2015. These complaints have been organized in a database and analyzed considering: i) types of noise source (technical facilities, music, transport infrastructures, etc.); ii) business/leisure activities (retail and catering businesses, production, service sector, etc.) and iii) outcomes of the complaints inspection by local authorities. In addition, by means of a GIS software, the territorial distribution of noise complaints has been determined according to the noise source category and disturbing activity. This analysis includes also a geo-statistical representation by density maps. The results show that, even though road traffic is the dominant noise source in residential and urban areas, the perception of other noises, such as those from industrial facilities, civil construction and social activities (parties, fairs and open air markets, residential noise, etc.), is perceived as more annoying. The results show that since 2007 the number of noise complaints (about 100-150 complaints/year) remains almost constant across the years. However, the spreading of leisure activities, malls, exhibition centers and venues, as observed for the years 2014-2015, would most likely grow them even more. This outcome can assist the local authority in the management of the activities in order to reduce their harmful impact on the population.