Abstract: To investigate the risk of exposure to toxic and harmful gases during the profession of fire scene investigators, this paper designs an experimental method based on mass spectrometry detection technology. By collecting environmental gases at fire scenes, we identify the components of toxic and harmful gases, and by then collecting the exhaled breath of fire investigators, we determine the main components of human exhaled breath. Finally, by analyzing the changes in the exhaled air of fire scene investigators, further conclusions can be drawn. The results show that environmental gases at fire scenes contain various volatile organic compounds that are harmful to human health. Human exhaled breath does not contain exogenous compounds from the fire scenes. However, the analysis of exhaled breath before and after entering the fire scene reveals significant differences in the protective effects of different protective equipment against toxic and harmful gases. Improper selection can lead to the inhalation of a substantial amount of toxic and harmful gases, posing a threat to human health. Although human metabolism can expel exogenous toxic and harmful substances, personal protection is still necessary. Therefore, it is recommended that fire investigators reasonably select and wear respiratory protective equipment during their profession to prevent the hazards of toxic and harmful gases in their work and ensure personal health.

Key words: fire scene investigation, exhaled breath, exposure risk, toxic and hazardous gases