  Nowadays, many technological advances applied to the Internet of Things (IoT)
make the introduction of innovative sensors aimed to deploy efficient wireless
sensor networks possible. In order to improve the environment and people's
lives, real time analysis of certain environmental variables may favor the
reduction of health risks related to the deterioration of air quality. To this
respect, the proposed system implements a particular prototype of IoT device
characterized by the assembly of ambient sensors capable of measuring pollutant
gases, temperature and humidity. For this purpose, Raspberry Pi and Arduino
platforms are used. Several security methods are introduced to ensure the
integrity of air quality data by implementing Merkle Trees on each IoT node and
on the Cloud server. Besides, the authenticity of IoT devices and the
confidentiality of communications are guaranteed by implementing HTTPS
requests. Finally, authentication tokens are used to identify system users, and
different security rules are applied to manage database operations.
