European Initiative Advances Digital Twin Technology for Cleaner, Healthier Cities

Urban air and noise pollution are silent threats affecting millions of Europeans every day. The HARMONIE project (Health Assessment Refinement for Mitigating Noise and Air Quality Effects) brings together European experts in environmental science, public health and digital technologies to develop advanced tools that support cleaner, healthier and more equitable urban environments. Funded under the Horizon Europe call “Zero-Pollution Cities,” contributing to the EU Mission “Climate-Neutral and Smart Cities by 2030,” the project improves monitoring and modelling of air pollution and noise while providing tools to evaluate the health impacts of urban actions in both the short and long term.

HARMONIE works across two interconnected environments: real-world pilot studies and advanced digital twin simulations. In its five pilot cities, Barcelona, Lausanne, Sarajevo, Gävle and Barakaldo, the project collects detailed data on air and noise pollution, including emerging indicators such as oxidative potential (OP), as well as citizen mobility patterns, exposure levels and health indicators, with a particular focus on vulnerable populations.

These real-world insights feed into two complementary digital twin systems. The Lung Digital Twin (LDT) models how pollutants interact with the human respiratory system. It simulates airflow and the transport and deposition of inhaled particles inside the airways, enabling detailed assessments of inhaled dose and health impact pathways.

The Citizen-Centric Digital Twin (CCDT) integrates pollution mapping with mobility patterns, social dynamics and exposure modelling to show where people are exposed to pollution and enables “What-If” simulations that allow policymakers to test potential urban measures in a safe, data-driven environment.

Swiss TPH’s contribution

Swiss TPH’s Physical Hazards & Health Group is leading the work to quantify health impacts attributable to air pollution after policy interventions in case studies and digital twin models, while the Systems Innovation Research Group is contributing to the development of the digital twin model and leading engagement with policy stakeholders. This involvement reflects Swiss TPH’s strategic focus on climate and environment and its commitment to translating scientific evidence into actionable urban health solutions.

HARMONIE’s holistic approach advances environmental monitoring and modeling while placing citizen engagement and behavioral insights at the centre of zero-pollution strategies. The initiative provides open-source, scalable digital solutions for all cities and populations, supporting the EU’s broader ambitions for climate neutrality, health equity, and zero pollution in at least 100 European cities, with the potential to expand globally.

About the project

HARMONIE coordinated by the Barcelona Supercomputing Center (BSC) and includes 19 partner institutions: Universidad de Deusto, Bettair Cities SL, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Fondazione Bruno Kessler (FBK), University of Bristol, Factual Consulting SL, Max Planck Institute for Chemistry (MPIC), Pompeu Fabra University (UPF), Swiss Tropical and Public Health Institute (Swiss TPH), Unisanté – University of Lausanne, Air Quality Consultants (AQC), the City of Sarajevo, University of Gävle, the Diputació de Barcelona, the Barakaldo Municipality, University of Nova Gorica, University of Basel, and the Lausanne Municipality.

The project has received funding from the European Union's Horizon Europe programme under grant agreement No 101238943, and the State Secretariat for Education, Research and Innovation (SERI).