Evaluation of the environmental sound in the city of Porto

Abstract

Noise pollution, mainly derived from road traffic, is an increasing threat to the citizens' well-being and public health. Thus, its monitoring and consequent mitigation are crucial. The development of noise maps allows to achieve these goals. Traditional methods of noise mapping have limitations and measuring equipment is expensive. One solution is the adoption of low-cost technologies. Although they have low reliability, these technologies can be deployed in multiple locations, allowing a high resolution "mapping". In Oporto, one environmental monitoring platform was developed using low-cost sensors: the UrbanSense Platform. This platform is composed by different types of sensors that measure weather conditions, noise and air quality parameters. Each one of these sensors has been installed in areas of influence of major noise and pollution sources as well as in public areas in Oporto. During a period of ten months, the sound information captured by the various noise sensors was analyzed in order to understand which are the main noise sources in the city. Since these are low-cost sensors, its accuracy isn't as reliable as other certified and calibrated equipment. Thus, to obtain a suitable calibration model for these sensors, were carried out various field measurements using a sound level meter. The data extracted from UrbanSense Platform were inserted in a geostatistical software, Surfer11, which allowed to obtain a 2D spatial dispersion of noise by the Oporto city. Although the platform had a lack of sound information, it was concluded that the most noise-critical areas are mainly due to road traffic. However, it was not possible to obtain a calibration model.