Imagine a scenario where Chennai’s residents can access real-time air quality data of their surroundings to decide whether to step out, stay home, or avoid certain routes. This level of air pollution monitoring could well be a reality soon.
Currently, Chennai relies on two main systems of air quality monitoring — manual monitoring stations and Continuous Ambient Air Quality Monitoring Stations (CAAQMS). While these are crucial, theoy come with high operational costs; around Rs 3 lakh for manual stations and several crores for CAAQMS setups.
The Indian Institute of Technology Madras (IIT-M) has developed a mobile air pollution monitoring sensor that can give hyperlocal insights at a fraction of the cost of CAAQMS. As part of Project Kaatru, this initiative aims to empower individuals and communities to make informed decisions about their environment.
An earlier article explained how air pollution levels are monitored in the city. In this interview with Citizen Matters, Professor Raghunathan Rengaswamy, Dean (Global Engagement) and Faculty, Department of Chemical Engineering, IIT-M talks about the need to capture hyperlocal data and how Project Kaatru can serve as a powerful communication platform to flag air pollution levels in cities like Chennai. Sreejith C (Postdoctoral Researcher) and Sumeer S (Research Scholar) from the air pollution monitoring sensors development team were also present.
Read more: Air Pollution: More blue days than blue skies in India’s cities
Excerpts from the interview
Insights into Project Kaatru
Can you tell us about Project Kaatru and why it is significant?
Traditionally, air quality is measured at fixed locations using monitoring stations. These stations, however, only represent air quality within a small geographic area. The reality is that air pollution is highly dynamic, with locations just a few hundred metres apart experiencing vastly different pollution levels, and these levels can change throughout the day.
It doesn’t make sense to broadly state that “Chennai’s air quality is good” or “bad.” Some areas are severely polluted, while others may have relatively cleaner air. However, setting up more monitoring stations is not a feasible solution due to the high costs involved. This is where our mobile solution comes in. Our devices can be mounted on vehicles, enabling us to capture a spatio-temporal map of pollution across the city.
Measurement of various pollution sources
What kind of data does the device capture?
Our mobile sensor captures various pollution parameters, including particulate matter (PM1, PM2.5, PM4, and PM10), temperature, humidity, gaseous concentrations such as carbon dioxide, hydrogen sulphide, ozone, sulphur dioxide and nitrogen dioxide, and other volatile organic compounds. It also measures ambient light (UV and infrared radiation) and environmental factors such as wind speed, wind direction, and rainfall.
How do you validate this data?
Every measurement technique can have errors. Our sensors follow approved standards, though we recognise that they might not align perfectly with the Pollution Control Board’s (PCB) measurements, as we use different technologies. Instead of focusing on exact numbers, we prioritise qualitative validation. When the PCB reports high pollution, we verify that our devices also indicate elevated levels; similarly for low pollution levels.
The standards for this new technology are still evolving, but we are working on refining them. Once the data validation is complete, we plan to submit our findings to an appropriate agency for further standardisation. This process is currently going on.
Mobile solutions for better results
How does your technology differ from the existing monitoring systems in Chennai?
The key difference is that both manual and CAAQMS stations in Chennai are stationary, whereas our technology can be used both stationary and mobile. The ability to monitor air quality while in transit allows us to map pollution parameters dynamically, a feature that current monitoring systems cannot capture.
While both the PCB’s systems and our devices measure particulate matter, our technology provides detailed data from multiple locations, even on the ground level, throughout the city. This is something that stationary stations cannot do. Moreover, our devices cost between Rs 50,000 to Rs 1 lakh, depending on the sensor type. If mass-produced, the cost could drop even further, making it a cost-effective solution compared to traditional methods.
Setting up a new monitoring station requires significant infrastructure, including real estate and constant data monitoring. In contrast, our device is portable and can easily be mounted on a vehicle to collect data.
Hi-tech solution for air quality monitoring
How do you think your technology will be a changemaker?
Once widely adopted in Chennai, citizens could get air quality data for specific locations based on GPS coordinates. If someone provides their lifestyle profile, we could estimate how much pollution they are likely to inhale during their daily commute. This would empower individuals to make informed decisions, such as avoiding high-pollution routes.
In the long term, the data we collect could be used to make the city smarter — improving air quality, traffic regulation, and urban planning.
Crowdsourcing data to monitor air pollution in Chennai
In the Kaatru web portal, we see that the devices are being given to those who register. How many have got the devices in Chennai so far?
Currently, we have not yet opened bookings for Chennai. However, as part of a pilot study, we’ve deployed five stationary and five mobile devices in Koyambedu. We are looking into the aspects of the data validation and stability of these devices in the ongoing pilot study.
However, in Gurugram, where pollution levels are quite high, we have deployed 40 stationary and 40 mobile devices.
We’ve also received significant interest from MSMEs, particularly from factories that need to monitor air quality regularly for regulatory compliance. These companies currently hire consultants to monitor pollution levels, but with our devices, they could monitor pollution in real-time at a fraction of the cost.
When mass production starts, the price will also come down and then we will pitch it for the personal use of individuals.
Read more: Industrial pollution in Chennai: Through the lens of the toxic tour
Bridging the communication gap
Monitoring air pollution is often seen as the government’s work but your initiative gives these devices to the public as well. Why do you think the device should be available for individuals?
Typically, monitoring air pollution is seen as the government’s responsibility. However, we believe that this should be a shared responsibility between citizens and the government. The government has limitations, but crowdsourcing data can help bridge these gaps.
For instance, Google Maps gives a reasonably accurate estimate of travel time to go from one place to another. That is because it is crowdsourcing data from multiple mobile phones.
If we make these devices affordable, we could encourage citizens to invest in them and use them to collect air quality data. By mounting the sensors on vehicles, individuals could actively contribute to pollution mapping across the city. This will make the individuals part of the solution rather than waiting for the government’s intervention. Imagine: If 10,000 people across Chennai collect real-time air quality data, we could create a detailed pollution map to inform policy decisions and regulate traffic more effectively. The collective information can be used to minimise our exposure to harmful air.
How will your technology help bridge the communication gap on air pollution?
One of the key features of Project Kaatru is its web portal, where real-time air quality data from all the devices will be made available to the public. Once there are enough devices and we are confident about the values we are giving, any citizen can go to our website and check for the air quality of the particular area. This website will itself serve as a communication platform.
Key findings and plans for expansion
Can you share some of the key findings from the study and the insights you gained from it?
The air quality changes drastically every 100 metres. People know this but there is not enough data to support it. We now have enough data to support this claim.
We did a specific pilot study in Ambattur. Interestingly, one specific location showed a significant spike in PM2.5 pollution between 2 am and 3 am. This was associated with trucks carrying milk from a major milk distribution hub in this location at this time. Spikes in PM2.5 were also found in school neighbourhoods during school start and end hours and in commercial zones during peak hours.
We have also explored adding a three-dimensional accelerometer to the device to track road conditions in real-time, which could provide additional valuable insights.
How are you planning to take the project forward?
It’s difficult to get hyperlocal information. You have to have standards. It is very critical for many things. Technologies like this are the only viable option at present, capable of offering high spatio-temporal awareness that could allow for informed mitigation and policy decisions. Validating this data is our responsibility. Once it is done, if the government is interested in trying to implement this, we will be in a position to expand it across the city.