Sensor.Community is a bottom-up initiative of citizens who seek to contribute to the creation of open environmental data.The community facilitates access to low-cost sensors, helps visualise the collected data. The main focus of the initiatives is on air quality (PM 2.5 and PM10) and noise monitoring. So far, its interactive map displays more than 17 billion data points from 14,000 sensors worldwide. The Dutch National Institute for Public Health and the Environment (RIVM) aims to increase data comparability across Europe and further integrate citizen science data into its databases. In collaboration with other initiatives such as Sensor.Community, the RIVM has developed a data infrastructure that has informed other projects like Snuffelfiets (“Sniffer Bike”) or Hollandse Luchten (“Dutch Skies”). 54 Visit the project website