Multiple cities
air quality

Breathable Cities: Measuring air quality and real-time emission levels using sensors on the buses in London, Aarhus and Santander

Team: Leapcraft

Leapcraft used CPH Sense (environmental sensors) on city buses in London, Aarhus and Santander for measuring air quality and emission levels in real-time to improve city planning, environmental policy-making and offer services for citizens to reduce their exposure to air pollution. “Breathable cities” experiment aimed to create a scalable solution to enhance transparency, fairness and compliance with air quality regulations.

The Team

The key members include: Vinay Venkatraman (CEO), Anne Cecilie Duus Kühnel (Operations Manager), Rohit Sharma (Creative Technologist), Vignes Krishnamoorthy (Engineering & Data Analyst), Christian Sonne (Software Developer), Emily Frimand (UX Engineer & Project Manager), Prima Mani (Design Researcher).


“Improving air quality is crucial to cities around the world. In our project we have been trying to gather measurements in movement. Succeeding with this would give a possibility of doing real-time measures covering a whole city with less devices. This could potentially improve air quality greatly.”



1. Relationships with bus companies were built for all three cities, then technical installation of sensors and displays for the bus were specified.

2. Data integration structure was built through an extensive use of the OrganiCity platform and tools.
3. Data visualisation was developed and hardware for sensors was produced. Then sensors were mounted on buses to start monitoring air quality.

4. The real-time data was shown to citizens to receive their thoughts and feedback.

Experiment outcome

Graphs and heatmaps: We produced graphs and heatmaps to show an overview of the NO2 levels from sensors installed on buses in Aarhus. This city was expected to have normal pollution levels, however, we saw that measures exceeded the EU hourly regulations. This was also surprising to the citizens of Aarhus.

Sensors for measuring air quality: CPH Sense were mounted on buses to measure air quality while on the move, at various times and locations. They were mounted on the front of all buses to connect to the bus battery and avoid misleading measures from the exhaustion of the bus.

Disseminating our experiment: We have shared our experiences and impact of the experiment at various trade shows such as Smart City Expo in Barcelona, Utility Week in Amsterdam and Technomania in Herning.

Lessons learned

    1. Mobile sensors: By creating a moving network of sensors we are able to do a more precise mapping of a city with less sensors involved. This gives a great picture of how air quality is affected during certain periods of the day, for example during rush hours.
    2. Public awareness: During our experiment we learned that one of the key issues of air pollution in cities is the lack of awareness amongst citizens. Most interviewees were surprised when they were shown graphs of air quality in their city. Most of them didn’t expect their city to exceed EU regulations.
    3. Connectivity: We learned that when the sensors undergo constant movements in dense cities like London, the connectivity is more likely to fail, causing a gap in the measurements. Thus, adjustments need to be made for a better connectivity.

Leapcraft Twitter
Leapcraft Facebook page

What happened & what's next?

  • We are creating marketing material from gathered insights.
  • We are also looking at a new strategy for a similar future project.
t_footer(); ?>