Riga Pilot Report

There were two citizen science campaigns implemented in the Riga pilot in 2024 and 2025. The first campaign lasted 2 years while the second lasted one year but both were diverse with approaches, results and lessons learned. Both campaigns yielded important experiences to develop further within the Urban ReLeaf project and in upcoming projects implemented in the Riga planning region. Air Quality Campaign (Riga, 2024–2025) - "Adopt a sensor" Purpose: Assess the role of greenspaces in reducing PM2.5 exposure and improving public health.Approach: Installed 20 low-cost PurpleAir sensors across diverse sites (urban green, near-green, near-traffic, traffic) to complement two regulatory stations. Engaged citizens via “Adopt a Sensor” open call; strong volunteer response (40 applications). Developed partnerships with municipal institutions, educational organisations, and non-governmental organisations (NGOs). Initiated cooperation with Riga Digital Agency to create a citywide data visualisation platform. Results: Over 87,000 mean observation hours collected in Year 1; indicative trends align with official monitoring. Urban greenspaces consistently linked to lower PM2.5 exposure, though not fully isolated from traffic/domestic emissions. No exceedances of EU short-term PM2.5 thresholds; annual averages suggest localized hotspots. Data supports arguments for low-emission zones and greening strategies in Riga. Lessons Learned: Citizen engagement exceeded expectations; volunteers remain committed beyond campaign. Clear communication and technical readiness are critical for sustained participation. Expansion of sensor network and integration into city planning recommended. Heat Stress Campaign (Riga, Summer 2025) "Step towards greener city" Purpose: Raise awareness of urban heat islands and the role of greenery; involve citizens in temperature and relative humidity (TRH) data collection.Approach: Distributed 54 TRH sensors; collected ~49,000 paired observations via EcoPulse app. Organised educational events and thematic walks to strengthen community engagement. Collaborated with related projects (LIFE LATESTadapt, SATSDIFACTION) for knowledge exchange. Findings: Recorded temperatures ranged from 9.6°C to 40.2°C; mobile TRH sensors showed ~4.4°C higher readings than reference stations, confirming heat island effects. Data highlights cooling benefits of green spaces and need for improved urban design. Technical challenges with app usability affected participation; WhatsApp community support proved essential. Lessons Learned: Citizen science is effective for awareness and data collection but requires user-friendly technology. Future campaigns should improve technical reliability, maintain strong communication, and explore gamification for motivation. Strategic Impact and Next Steps Urban ReLeaf has strengthened Riga’s capacity for data-driven environmental governance. Ongoing development of a citywide data visualisation platform will enable broader use of collected data. Recommendations include expanding sensor networks, improving citizen engagement strategies, and leveraging findings for greening plans and low-emission zones. Continued collaboration with EU projects and local stakeholders will ensure alignment with climate neutrality goals.