Periodic Reporting for period 2 - Urban ReLeaf (Citizen-powered data ecosystems for inclusive and green urban transitions)
Período documentado: 2024-05-01 hasta 2025-12-31
European cities face escalating environmental pressures, including air pollution, rising heat stress, and uneven access to safe and high-quality green spaces. These pressures affect health and well-being and can deepen inequalities, as some neighbourhoods have fewer trees and less cooling from nature. Many cities want to expand nature-based solutions, but they often lack fine-grained, locally trusted evidence on where action is most needed and how people experience heat and green space in daily life.
Urban ReLeaf uses citizen science to strengthen inclusive urban greening. It brings residents and public authorities together to improve the evidence base for decision-making. The project combines citizen observations with low-cost sensing and Earth Observation to produce information that cities can use for planning, monitoring and policy. Participation is designed to reach diverse groups and neighbourhoods, including vulnerable or marginalised communities.
Urban ReLeaf works with six pilot cities that test policy-oriented campaigns. These include participatory tree registries, thermal comfort mapping that identifies hot spots and comfort zones, and community air quality monitoring in traffic-affected areas. The pilots also link sensor data with perceptions of heat and park quality, and explore integration into municipal systems so results can support day-to-day workflows.
The project starts from city needs and co-designs campaigns with local stakeholders. It runs repeated cycles and delivers quality-assured, reusable datasets and tools that can support decisions on tree management, greenspace improvements, heat risk reduction and air quality actions. Over time, this approach can strengthen partnerships between residents and public authorities and enable more equitable, data-driven urban planning.
Social sciences and humanities are integrated through participatory methods that capture perceptions, lived experience and barriers to participation, supporting trust and long-term uptake in governance.
Urban ReLeaf uses citizen science to strengthen inclusive urban greening. It brings residents and public authorities together to improve the evidence base for decision-making. The project combines citizen observations with low-cost sensing and Earth Observation to produce information that cities can use for planning, monitoring and policy. Participation is designed to reach diverse groups and neighbourhoods, including vulnerable or marginalised communities.
Urban ReLeaf works with six pilot cities that test policy-oriented campaigns. These include participatory tree registries, thermal comfort mapping that identifies hot spots and comfort zones, and community air quality monitoring in traffic-affected areas. The pilots also link sensor data with perceptions of heat and park quality, and explore integration into municipal systems so results can support day-to-day workflows.
The project starts from city needs and co-designs campaigns with local stakeholders. It runs repeated cycles and delivers quality-assured, reusable datasets and tools that can support decisions on tree management, greenspace improvements, heat risk reduction and air quality actions. Over time, this approach can strengthen partnerships between residents and public authorities and enable more equitable, data-driven urban planning.
Social sciences and humanities are integrated through participatory methods that capture perceptions, lived experience and barriers to participation, supporting trust and long-term uptake in governance.
During the second reporting period, Urban ReLeaf shifted from preparation into full pilot delivery and early integration. Two seasonal campaign cycles were implemented across all six pilot cities, covering trees, greenspace perceptions, heat stress and air quality. Cities used a mix of citizen observations, low-cost sensing and Earth Observation to address concrete local questions.
Key technical and scientific achievements include the deployment and operation of low-cost sensor systems for air quality and temperature and humidity monitoring, the use of citizen-facing digital tools in real campaigns, and the refinement of data quality methods that increase trust and usability. The project also produced high-resolution Earth Observation layers, including tree canopy and individual tree crown products, providing a consistent spatial baseline that can be linked to citizen and sensor data.
- 6 pilot cities and two seasonal campaign cycles (2024 and 2025) delivered in each city.
- 3,700+ citizens mobilised by M36 across pilots.
- 41 fixed low-cost air-quality monitors installed across Athens and Riga
- 230,000+ measurement hours of air quality in Riga and Athens
- 450,000+ temperature and relative humidity observations across pilot cities
- 2500+ surveys of greenspace perception completed
- 110+ parks, greenspaces and open spaces investigated
- 350+ wearables deployed for measuring urban heat stress
Key technical and scientific achievements include the deployment and operation of low-cost sensor systems for air quality and temperature and humidity monitoring, the use of citizen-facing digital tools in real campaigns, and the refinement of data quality methods that increase trust and usability. The project also produced high-resolution Earth Observation layers, including tree canopy and individual tree crown products, providing a consistent spatial baseline that can be linked to citizen and sensor data.
- 6 pilot cities and two seasonal campaign cycles (2024 and 2025) delivered in each city.
- 3,700+ citizens mobilised by M36 across pilots.
- 41 fixed low-cost air-quality monitors installed across Athens and Riga
- 230,000+ measurement hours of air quality in Riga and Athens
- 450,000+ temperature and relative humidity observations across pilot cities
- 2500+ surveys of greenspace perception completed
- 110+ parks, greenspaces and open spaces investigated
- 350+ wearables deployed for measuring urban heat stress
Urban ReLeaf goes beyond the state of the art by combining three elements in one operational approach: citizen observations and lived experience, scalable low-cost sensing with quality control, and consistent high-resolution Earth Observation products. The project is not only generating data, but also developing practical workflows so that cities can use these data in planning and governance.
Key results include:
- Multi-city citizen-powered datasets on heat stress, air quality, greenspace perceptions and urban trees, collected through repeat campaign cycles and designed for reuse.
- Practical, implementation-tested tools and protocols that lower barriers for cities to run citizen science campaigns and manage resulting datasets.
- Early integration steps with city platforms where available, demonstrating a route from community measurements to municipal systems.
Potential impacts:
- Better prioritisation of greening and cooling measures by identifying hotspots, “cool spots,” and discomfort areas that matter to residents.
- Stronger targeting of air quality actions through indicative high-resolution exposure patterns.
- Improved urban tree information for maintenance, protection, and planting strategies.
- Increased trust in citizen-generated evidence through clearer quality and governance safeguards.
Key needs for further uptake and success:
- Continued work on standardised publication packages, metadata, and open access pathways to make datasets easier to find and reuse.
- Clear guidance for authorities on quality thresholds, validation practices, and how citizen data can complement reference monitoring.
- Supportive governance and procurement conditions so cities can maintain low-cost sensing and data stewardship after the project.
- Practical adoption resources, including templates and step-by-step guidance, to help additional cities replicate the approach.
Key results include:
- Multi-city citizen-powered datasets on heat stress, air quality, greenspace perceptions and urban trees, collected through repeat campaign cycles and designed for reuse.
- Practical, implementation-tested tools and protocols that lower barriers for cities to run citizen science campaigns and manage resulting datasets.
- Early integration steps with city platforms where available, demonstrating a route from community measurements to municipal systems.
Potential impacts:
- Better prioritisation of greening and cooling measures by identifying hotspots, “cool spots,” and discomfort areas that matter to residents.
- Stronger targeting of air quality actions through indicative high-resolution exposure patterns.
- Improved urban tree information for maintenance, protection, and planting strategies.
- Increased trust in citizen-generated evidence through clearer quality and governance safeguards.
Key needs for further uptake and success:
- Continued work on standardised publication packages, metadata, and open access pathways to make datasets easier to find and reuse.
- Clear guidance for authorities on quality thresholds, validation practices, and how citizen data can complement reference monitoring.
- Supportive governance and procurement conditions so cities can maintain low-cost sensing and data stewardship after the project.
- Practical adoption resources, including templates and step-by-step guidance, to help additional cities replicate the approach.