The Role of Natural Ventilation and Interior Layout in Enhancing Indoor Air Quality

Indoor air quality (IAQ) impacts health, comfort, and effectiveness in residential spaces, especially in tropical cities like Lagos, Nigeria. This study looks into the complementary function of natural ventilation (NV) and interior spatial layout in improving IAQ in middle-income apartment buildings. The study uses a convergence parallel mixed-methods approach, combining field-based IAQ monitoring, Computational Fluid Dynamics (CFD) simulations, and architectural layout analysis to assess the relationship between building design and air performance. Open-plan layouts with cross ventilation meet the highest IAQ standards, dramatically reducing CO₂ and PM2.5 concentrations. Compartmentalized arrangements with single-sided ventilation perform poorly. Seasonal fluctuations also have an impact on indoor air quality, with the wet season increasing pollutant collection in poorly ventilated rooms. The study presents evidence-based design methods for healthier tropical housing while calling for better policy frameworks and layout-conscious planning. It suggests better alignment of apertures, fewer internal obstructions, and orientation to prevailing winds as critical considerations for sustainable urban home architecture. Future studies should look at smart ventilation technology and broader regional applications to improve indoor environmental quality.