On May 17, 2019, 30 cyclists literally kicked off to measure the air quality on their bicycles. A measuring box with a sensor on each bicycle maps their route and measures the air quality along the way. In this project, RIVM indicates the real-time collected data. It is difficult to measure air quality accurately with small sensors. That is why RIVM ensures continuous calibration of the sensors, so that the quality and reliability of the data is as good as possible.