GreenAir is a hardware social project that seeks to monitor the level of air pollution in cities around the world. It is a network of sensors with that samples the air and analyzes the composition of the air and sends the result to a web interface for recording and display. Air pollution problem is a major challenge that is closely connected with global warming. It has adverse effect on our health especially the health of infants. We need a system that helps us to create awareness of the the problem at hand. It is when we are aware of the problem at hand that we will be able to act accordingly. GreenAir consist of two part, the hardware and the monitoring interface. The hardware consist of sensors for sampling the air. The data sampled is analyzed on the hardware and it is sent to the monitoring interface where it is displayed in graphical format.