air quality

Green Biking Routes: Low-cost sensors to help identify green routes in the city for cyclists and explore Personal Health Exposure (PHE)

Team: BioDigital Health

The Green Biking Routes sought to help cyclists identify green routes of low air pollution exposure in cities. The experiment selected citizens living and cycling in Aarhus and equipped their bicycles with low-cost sensors to measure air quality. The test participants followed their ordinary routes to work and around town, then followed a low exposure ‘green’ route.

The Team

The key members are Ian Glasscock and Rebecca Weicht from BioDigital Health.

"In Denmark biking is a popular mode of transport when commuting in the city, and Danish cyclists bike around 3 million kilometres every year. Many of those kilometres are along highly trafficked streets which means they are exposed daily to air pollution from the local urban traffic. However, choosing an alternative route along less trafficked streets might increase the distance a little but could potentially reduce air pollution exposure significantly.”


1. Collecting air pollution data through low-cost sensors on ordinary cycling routes

Test participants installed low-cost air pollution sensors on their bicycles to measure concentration levels along their ordinary routes between work, school, or shopping. The sensor collected real time measurements and stored them together with geolocation and time data on a tablet. (
Image: The sensor box and the reference monitor mounted at the rear rack on a bike)

2. Collecting air pollution data along low exposure ‘green’ routes
Based on traffic data from the Open Data Aarhus platform, ‘greener’ routes of lower air pollution were identified that the test participants then took.
 (Image: CO2 concentration measured by the sensor box at a bus station in Aarhus)

3. Data analysis and personal exposure levels
Team then compared concentration levels of air pollutants between the different routes. We learnt that the personal pollution exposure can be reduced when choosing a ‘green’ route through city. (Image: Total cumulative exposure for a user based on the actual exposure of the journeys they completed (from: Air Quality Exposure, , 2017))

Experiment outcome

Improved sensor box and improved access to air pollution sensors
We were able to show the benefits of and further improve low-cost air pollution sensors through corrections and adjustments for mass usage of cyclists. Air pollutant analysers are relatively large, heavy and expensive, with prices ranging between €1000 and €30,000 per device. The insights gained can make air pollution sensors available to the mass market allowing commuters to understand their ‘personal exposure’ levels and make travel decisions that will be beneficial to their health. In addition, small, personal air pollution sensors will allow smaller cities or underdeveloped regions to monitor air quality.

‘Green’ bicycle routes for Aarhus identified
Thanks to the accurate datasets collected, less polluted ‘green’ routes could be identified for Aarhus cyclists.

Lessons learned

Low-cost sensors can be applied in smart cities to benefit citizens
    Our laboratory tests showed that after upgrading sensor box and further calibrations, emerging low-cost sensors can be applied for smart cities to indicate street levels of personal exposure; this can be linked to city pollution models to provide green areas, and be harnessed by all citizens to reduce personal exposure during their daily commutes.

BioDigital Health Website

What happened & what's next?

  • We (BioDigital Health) were awarded an innovation grant to integrate a variety of sensors into a cloud Internet of Things and target refinement of Personal Exposure Model (PEM).


Hertel, O., et al. (2008). "A proper choice of route significantly reduces air pollution exposure--a study on bicycle and bus trips in urban streets." Sci Total Environ 389(1): 58-70.

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