Air pollution is a major threat faced by all cities in the world. However, in metropolitan cities, especially in developing nations, the infrastructure for monitoring air quality is insufficient. The government cannot afford to install air pollution monitoring stations because of the high cost associated with it. Moreover, present-day monitoring solutions are inadequate in monitoring several locations spread across the city.
Design Idea: How it Works
To effectively solve the problem, a solution is needed that provides an accurate estimate of pollution in real time, as well as be economically viable for governments and local bodies to install it. This can be achieved by deploying a Wireless Sensor Network.
A Wireless Sensor Network consists of several nodes, called ‘motes,’ installed at different locations. Each mote contains a number of gas and particle sensors, a microcontroller, transceiver, and a power supply unit. Each mote collects concentrations of various gases and sends this data to the base station for processing and analysis.
The data collected by each mote is routed through the network and forwarded to the base station by using energy-efficient routing algorithms. Once the data has reached the sink node (base station) through the network, it is uploaded to the cloud by the sink node.
Once data is collected and uploaded to the cloud, it is processed and analyzed. With this data, a heat map is plotted for various pollutants as well as the overall Air Quality Index across the network. This heat-map will be available on a website and mobile application for public viewing. The system would automatically send email notifications to industries exceeding the emission levels based on standards set by government. This would also help regulators as specifics about violations would be known.
What makes it Innovative
We decided to use a wireless sensor network to increase the density of monitoring. Present-day monitoring stations attempt to estimate the air quality in a city with the help of data collected at a few isolated stations across the city. This reduces the density of monitoring. Hence, a distributed system is essential to ensure that the region is being effectively monitored.
Another advantage is Scalability. To increase the area being monitored, simply new nodes need to be added to the network. This would’ve been extremely expensive with present-day monitoring stations.
In order to save power, internet connectivity will not be provided to each node. This also reduces the cost incurred per node. The sink node is the only one in the network that needs to be connected to the internet for uploading data on the cloud. We would be having multiple base stations to ensure that failure in one station doesn’t affect the whole network.
Machine Learning Algorithms will be used to develop estimation models for calculating the spread and directivity of pollutants. This is a crucial step in this project as data collection at different points does not help in achieving the final goal. This data needs to be aggregated across the network to provide the spread and directivity of pollutants across the region. For this purpose, estimation models need to be developed according to the spread and directivity of pollutants under different circumstances. This step is crucial in integrating data collected at several nodes and generating a comprehensive pollution report out of it.
Over-The-Air Programming (OTA) will be used to provide software updates to all the motes from the base station, as it is impractical to program each mote by visiting their physical locations once the network is established.
Each mote will feature a renewable energy unit (solar panel). This unit will be used to keep the battery powered so that the lifetime of the mote is maintained. Ideally, the mote would be self-sustaining.
How would it be Produced
Each mote costs less than Rs. 1500 (USD 21.33) to produce. They are made with an easily available and widely used ESP8266 controller (with built-in transceiver) and MQ series sensors. The cost is further dropped when it is mass manufactured. We would require about 300 for an area of 32 sq.km.
Once the motes are ready, the governing body needs to install these motes at strategic locations on existing infrastructure like lamp posts, rooftops, mobile towers, etc. Once the network is set up, the data collected by the network can be monitored from the base station.
Currently, for preliminary testing, three motes and one sink node have been done. The mobile web-application has been developed. Theoretical studies for efficient routing in a network of hundreds of motes has also been conducted. Sustainability test with solar cells is being done.
Every person will have access to real-time air quality in their locality. This will help people suffering from respiratory diseases to avoid polluted areas consciously. Real-time pollution data will be available to citizens on their smartphones. This will increase awareness about the state of pollution in their city and locality. Also, the government can send push-notifications to citizen's smartphones announcing advisories based on pollution data.
This project will help thousands of cities worldwide to implement an effective air pollution monitoring system.