New route planning app to avoid air pollution debuts at Imperial lates

Attendees of the recent Imperial Lates event visited the data observatory to hear about a new app to help you avoid London’s dirty air.

The Data Science Institute (DSI) took part in the recent Imperial Lates event on 11 March 2025 themed around ‘Future Cities’.  

Imperial Lates are fun and social post-work events where you can learn about the latest scientific developments at Imperial College London. During the event, attendees had the opportunity to visit the DSI’s Data Observatory facility to hear about the Institute’s work helping to tackle London’s air pollution. 

In one project, students used Transport for London data and computer vision to track vehicles in traffic cameras. Attendees heard about how traffic congestion can help to provide estimates about air pollution in local levels through projects such as this.  

During the rest of the talk, visitors heard from former DSI Research Associate Dr César Quilodrán Casas, who talked about his work developing ‘Purify’ – a route planning application that integrates air pollution data and real-time traffic information to provide users with walking and cycling routes that minimise exposure to dangerous air pollution. This project was conducted in collaboration with MSc student Zeqi Li and Dr Rossella Arcucci, Director of Research from the Data Science Institute and was funded from the UKRI-IAA under the category of Smart Cities. 

‘Green routing’  

According to the World Health Organisation, air pollution is the largest environmental health risk, causing millions of premature deaths each year from respiratory and cardiovascular diseases.  

‘Purify’ which stands for ‘Pollution Updates and Real-time Information For You’ is an air pollution-based route planning web app for London. The app can help you to plan a walking or cycling route that avoids areas with higher levels of air pollution – this is known as ‘green routing’.  

Air quality sensors monitor the levels of particulate matter and nitrogen dioxide in the air. Hourly data from these sensors is downloaded through the Breathe London API (part of the Breathe London project run by Imperial and the Mayor of London).  

Users can input the origin and destination of a route, assisted by Google Maps Plugins and a layer of traffic data is added using TomTom’s API.  

The team created a Pollution Calculation Algorithm that integrates real-time traffic and air pollution data to estimate users’ pollution exposure along a route and will offer multiple routes for any user journey, including one that will avoid the dirtiest air.  

The Lates event was a great opportunity to present the Purify app to a public audience for the first time and to get their feedback.  

Most attendees thought the Purify App could be very useful: “I cannot wait to use this for cycling and running in London”.  

The Purify App will be available later this year - stay tuned for more information.