This study investigates the distribution of microorganisms in office buildings with weak natural ventilation. The relationship between indoor microbial air quality and factors such as ventilation, height, and indoor wind environment is explored in an office space in Guangzhou by employing microbial sampling, environmental monitoring, and simulations. The study aims to investigate the impact of weak wind speeds on the distribution of pollutants, with findings that could inform strategies for improving indoor environments in office buildings. The results showed that, under weak wind conditions, microbial concentrations in the office were positively correlated with wind speed in the morning. However, microbial concentrations were negatively correlated with wind speed at afternoon and evening. A comparison between the concentrations in regular activity areas and near-ground levels revealed that microbial concentrations near the ground were higher than those in the ventilated areas. Furthermore, both wind speed and the wind path influenced the distribution of pollutants indoors. The wind carried pollutants along its path, dispersing them throughout the space. Higher wind speeds reduced the residence time of pollutants, while lower wind speeds caused pollutants to accumulate in the area. Pollutants were also observed to stagnate in regions with low wind speeds, such as vortex areas, leading to local increases in pollutant concentrations.