This paper presents a network for indoor and outdoor
air quality monitoring. Each node is installed in a different
room and includes tin dioxide sensor arrays connected to an acquisition and control system. The nodes are hardwired or wirelessly connected to a central monitoring unit. To increase the gas concentration measurement accuracy and to prevent false alarms, two gas sensor influence quantities, i.e., temperature and humidity,
are also measured. Advanced processing based on multiple-input–single-output neural networks is implemented at the network sensing nodes to obtain temperature and humidity compensated
gas concentration values. Anomalous operation of the network sensing nodes and power consumption are also discussed.