Energy Efficient Real time Outdoor Air Quality Monitoring System.

Outdoor air quality monitoring (OAQM) is of great importance to human health and environment. Engineers and researchers are increasingly focusing their efforts on the design of real-time OAQM systems using wireless sensor networks. This paper presents an OAQM system enabling measurement of CO\n 2\n, CO, Cl\n 2\n, ambient temperature, and relative humidity. In our system, remote users usually employ a local gateway to connect wireless sensor nodes to the external world. In this work, the gateway processes the collected air quality data and transmits the useful data to end-users through a web-server. The nodes are self sustainable as they are equipped with a solar panel and a rechargeable Lithim-ion 2W 3.7V battery.