• The air pollution in the operating room has received less attention among the medical staff. • Using the well know PM2.5 index to evaluate the air pollution in the local area near the nose and mouth of chief surgeon at the experimental level • The liver tissue produced the highest concentration of PM2.5 in the operation, and the single-layer medical mask was not enough to filter it. • The surgical particulate respirator with the best preventive effect, filtered a large part of PM2.5, while it can't be used in long-term surgery for its poor air permeability, just can be considered for the short-time operation. • Current protective measures are not sufficient for the protection. Medical staff and managers should pay attention to this problem. The characteristics of the PM2.5 concentration in surgical smoke produced by operating on different human tissues during hemihepatectomy were explored to provide a reference for protective measures. Our results showed that the highest concentration of PM2.5 produced by the electrosurgical knife was the liver tissue, followed by muscle, adipose, and vascular tissue. When the single-layer disposable medical mask, double-layer disposable medical mask, and surgical particulate respirator were used to cover the sampling port of the detector, the PM2.5 concentration for all tissue types could be reduced by approximately 40%, 55% and 75%, respectively. In the liver, the average concentration of PM2.5 produced by the ultrasonic scalpel was approximately twice that produced by the electrosurgical knife, suggesting that the air pollution around the chief surgeon caused by the ultrasonic scalpel is more serious than that caused by the electrosurgical knife. Much more protective work should be given for the liver-related surgery. [ABSTRACT FROM AUTHOR]