Reliable and efficient solutions for a participative air pollution monitoring system

Air pollution is one of the leading causes of mortality worldwide. While some causes of pollution are strictly correlated to natural events, others are the effects of human activities. Fossil-fuel combustion and waste incineration are two of the main sources of pollution, dispersing in the air one of the most dangerous pollutants, the Particulate Matter (PM). The level of air quality is subject to regulation and it is monitored by the authorities that can impose countermeasures such as restrictions on the circulation of vehicles. Although fixed, official monitoring stations provide accurate environmental measurements, they are located only at certain points of the territory and therefore it is difficult to monitor all the areas in a pervasive way. The aim of this project is to contribute to the development of a smart system capable of monitoring air quality conditions through the use of tiny low-cost PM sensors in order to build a dense network of stations. A prototype of the system had already been developed but it was not suitable for experimentation due to performance and reliability problems. The system was designed to be a participative system in which citizens’ smartphones act as a gateway between the IoT device, which collect the environmental data, and the remote server, on which the data are stored and elaborated. The gateway is represented by a mobile application and the data transmission is made through the Bluetooth Low Energy technology. The objectives of this work are to design and implement solutions in order to fill up most of the performance and reliability gaps of the actual prototype. The realization of the system started from the improvement of data management on the IoT device in order to make the operations of load and store in a more efficient way. Then, the implementation of a new communication protocol was needed between the parts of the system, able to support and improve the reliability of the data transmission. In order to simplify the role of the user in the partecipative system and to ensure the proper operation of the communication protocol, a transparent and configurable background process was developed on the mobile application. Finally, to make sure that all the parts of the system work, the redesign and renovation of some web APIs on the remote server was necessary. The results obtained by the realization of this work show an increase in system performances, particularly in terms of data storage and data transmission time.