Long term monitoring of noise pollution in social gatherings places: time analysis and acoustic capacity as supports of management strategies

City of Torino (Italy), as many European cities, is facing noise pollution related to recreational noise of nightlife in open urban areas, such as streets, squares and terraces, where thousands of people meet spending all evening and night time. Noise from people speaking in these spaces can be very loud, due to crowd levels (since communication is possible only with a raised voice level) and people behavior. This study shows the analysis of long term noise data collected in two years by a low-cost IoT network in San Salvario area. It highlighted regularities on night levels, mainly on a weekly basis with a seasonality. Preliminary investigations on time series have been developed, in order to correlate noise levels and number of people involved, coupling environmental noise data and crowd sensors. Moreover, the concept of ‘Acoustic Capacity’ related to the noise levels has been investigated. This approach based on a deeper quantitative knowledge is explored as an help to local administration and stakeholders in planning and implementing mitigation actions.