A scientific tool for policymakers and architects to mitigate the spread of infectious disease
During the COVID-19 pandemic, policymakers and managers of indoor spaces were tasked to take fast decisions to mitigate its transmission, often without any scientific input available. At Cardiff University, we have been developing an indoor epidemic simulator to inform and mitigate future epidemic outbreaks. Unlike existing solutions, our simulator integrates detailed indoor geometry, architectural design and movement of individuals, along with novel mathematical models of virus spread and flow. The architectural design is undertaken through topologicpy, a well-established architectural digital design software developed at the Welsh School of Architecture (Jabi et al., 2025). The simulator can provide the infection risk of an infectious disease for a group of people in an indoor space with a given schedule (Xue et al., 2024).
References
2025
3D Topological Modeling and Multi-Agent Movement Simulation for Viral Infection Risk Analysis
This paper introduces an integrated method that combines computer-aided modelling of indoor environments, multi-agent movement simulation and airborne viral transmission modelling to analyse how spatial design and occupant behaviour affect disease spread. Using TopologicPy, interior spaces are represented as connected networks that support navigation-graph generation and agent movement based on schedules, walking speeds and activities. Agents move incrementally along shortest paths, while the system calculates precise inter-agent distances and respects architectural constraints such as walls and doorways. Viral aerosol concentrations are modelled via a reaction-diffusion equation, and infection risk is estimated using an extended Wells–Riley model. By capturing detailed spatio-temporal and topological interactions, the framework offers realistic infection-risk assessments. The resulting tool serves as a rapid decision-support system for policymakers, facility managers and designers, enabling evaluation of mitigation strategies and informing future building design. A comparative study of cellular and open-plan offices demonstrates the method’s capabilities.
2024
Modelling indoor airborne transmission combining architectural design and people movement using the VIRIS simulator and web app
A Viral Infection Risk Indoor Simulator (VIRIS) has been developed to quickly assess and compare mitigations for airborne disease spread. This agent-based simulator combines people movement in an indoor space, viral transmission modelling and detailed architectural design, and it is powered by topologicpy, an open-source Python library. VIRIS generates very fast predictions of the viral concentration and the spatiotemporal infection risk for individuals as they move through a given space. The simulator is validated with data from a courtroom superspreader event. A sensitivity study for unknown parameter values is also performed. We compare several non-pharmaceutical interventions (NPIs) issued in UK government guidance, for two indoor settings: a care home and a supermarket. Additionally, we have developed the user-friendly VIRIS web app that allows quick exploration of diverse scenarios of interest and visualisation, allowing policymakers, architects and space managers to easily design or assess infection risk in an indoor space.
