A coupled fluids-chemistry model for pollutant dynamics indoors—Application to a kitchen scenario

Indoor air quality (IAQ) is a critical factor influencing human health, particularly in confined spaces such as kitchens, where cooking activities release harmful pollutants. This study presents a novel modeling framework—ChemFlow3D—combining an in-house computational fluid dynamics (CFD) solver with a chemical reaction module to simulate the dynamics of both pollutant dispersion and transformation in a residential kitchen. The model captures the intricate interplay between fluid flow and chemical kinetics and is validated against experimental data for accuracy and reliability. Using this approach, the spatial and temporal distributions of common indoor air pollutants, including particulate matter (PM2.5), nitrogen oxides (NO and NO2), a generic volatile organic compounds (RH), and carbon monoxide (CO), were examined under various natural and mechanical ventilation strategies. The study also explored the impact of including chemical reactions on pollutant concentrations and compared this with simulations that neglected such reactions. The results show ChemFlow3D's ability to simultaneously account for ventilation strategies, pollutant transport, and chemical reactions. Validated against real-world measurements, the model successfully captures the evolution of indoor pollutants during cooking and demonstrates its robustness in simulating complex ventilation conditions. Additionally, the findings underscore the importance of accounting for chemical reactions, as reactive pollutants like NO2 exhibited notable transformations that were otherwise neglected. This work provides actionable insights into ventilation system design and optimization to mitigate indoor air pollution. It highlights the potential of integrating CFD and chemical kinetics for advancing IAQ research, offering a robust methodology to track the spatiotemporal evolution of pollutants in enclosed spaces.