Exposure and health risk assessment of indoor volatile organic compounds in a medical University

Many volatile organic compounds (VOCs) are used for experiments at universities, and most of them contain benzene, toluene, ethylbenzene, xylene, and an extraction solvent of dichloromethane. This study aimed to investigate the indoor concentrations of these five compounds in different locations on campus and to evaluate possible health risks for faculty members and students in a medical university. We selected 10 locations as sampling sites to conduct 4-h monitoring sessions on weekdays each season during 2019-2020. We used a 6-liter canister to collect air samples and analyzed these five VOCs via gas chromatography with a flame ionization detector. Monte Carlo simulation was performed to evaluate the carcinogenic and noncarcinogenic risks of these five VOCs. We found that dichloromethane was the most highly detected compound (median: 621.07 mu g/m3; range: 44.01-8523.91 mu g/m3), and the Department of Medicine had the highest concentration of the total of these VOCs among all of the locations (median: 5595.29 mu g/m3; range: 1565.67-7398.66 mu g/m3). The median carcinogenic risks of dichloromethane and benzene were 6.36 x 10-5 (95% confidence interval [CI]: 6.83 x 10-6-7.37 x 10-4) and 5.47 x 10-6 (95% CI: 4.03 x 10- 7- 2.42 x 10-5), respectively, for faculty members, and the lower risks of 3.14 x 10-5 (95% CI: 3.39 x 10-6-3.64 x 10-4) and 2.69 x 10-6 (95% CI: 1.97 x 10-7- 1.19 x 10-5) were estimated for the students. The chronic noncarcinogenic risks of four VOCs were less than one, except for dichloromethane with a median hazard index of 1.92 (95% CI: 2.11 x 10-1-2.22 x 101). This study observed the spatial variation in the concentrations of the total of five VOCs and dichloromethane. The carcinogenic risks were classified as being at the possible level, and the noncarcinogenic risk of dichloromethane was greater than the acceptable level. Increasing local exhaust ventilation during the experiment and reducing the using amount of dichloromethane are recommended actions to reduce VOCs exposures in the medical university.