**5. Working of the system**

The system proposes a design to fit monitoring applications on smartphones. Wireless sensors positioned at planned locations sense the level of carbon monoxide, nitrous oxide, humidity and temperature in the air. It provides simple access to the users to supervise real time air quality in their vicinity. It uses cost-effective and readily accessible devices such as an air quality sensor, carbon monoxide gas sensor, nitrous oxide gas sensor and SY-HS220 sensor. Microcontrollers are used at the sensor node for supervising these sensors. The sink node collects the data from sensor node and transfers it to the cloud database through wi-fi module. In the cloud, the data analysis is done so that the society takes measures to mitigate air pollution.
