The Impact of Residential Unit Layouts on Formaldehyde Diffusion and Removal: A Case Study of Typical Residences in Wuhan City

Indoor formaldehyde pollution poses a serious threat to human health, and residential layout design plays a critical role in formaldehyde diffusion. However, current research on the correlation between typical residential layout shapes and formaldehyde diffusion mechanisms remains insufficient. This study summarizes and refines five typical residential layout prototypes in Wuhan through investigation and employs CFD simulation to analyze formaldehyde diffusion patterns under three ventilation conditions: still-air condition, southeasterlies (dominant in summer), and northwesterlies (dominant in winter), with varying airflow speeds. Key indices such as the Human Health Risk Index and the removal rates are calculated, and the spatial distribution characteristics are evaluated by integrating airflow organization properties. The findings reveal that: (1) Under unventilated conditions, formaldehyde diffusion differs markedly by layout: the T-shaped layout shows more concentrated high concentrations. (2) Ventilation leads to layout-specific accumulation (dead zones, vortices), requiring tailored removal measures. (3) Most layouts achieve optimal removal efficiency at 1 m/s airflow speed (O-shaped, I-shaped, and L-shaped layouts), whereas F-shaped layouts require >0.5 m/s in summer and >1 m/s in winter; T-shaped layouts require case-specific solutions. Based on simulations, optimized ventilation strategies (targeted window-opening sequences, high-risk zone removal measures) are proposed. Results provide insights for early-stage residential design optimization in subtropical monsoon climates, improving indoor air quality.