The exposure risk of typical VOCs to the human beings via inhalation based on the respiratory deposition rates by proton transfer reaction-time of flight-mass spectrometer

The respiratory deposition rates are the important analytical parameters for human health risk assessment related to the environmental volatile organic compounds (VOCs). In present study, the deposition rates from the linear regressions of CH2O, CH5N, C2H6O, C2H4O2, C3H8O, C6H6, C7H8, C8H8, and C8H10 of 120 healthy volunteers were obtained with significantly different from the respective calculated deposition rates. The CH2O (formaldehyde) has the highest deposition rate, indicating the highest associated exposure risk of CH2O if the persons are exposed to the same concentrations of these VOCs through inhalation. In order to explore the effects of the breathing models and sampling time on the deposition rates of VOCs, volunteers were first asked to breathe successively with nasal-in-nasal-out, oral-in-nasal-out, and oral-in-oral-out breathing models before and after three meals for three days. Sampling time variation has no effect on the deposition rates of selected VOCs, while the deposition rates of C2H4O2, C3H8O, C6H6, C7H8 and C8H10 by nasal-in-nasal-out were significantly different from oral-in-oral-out and nasal-in-oral-out models. Among all the breathing models, nasal-in-oral-out comprises the entire respiratory system. In order to further validate the results, the deposition rates of the selected VOCs were calculated in 120 healthy volunteers using nasal-in-oral-out breathing model for unlimited time after the conventional lung function examination. Difference in gender and body mass index had no effect on the deposition rates of VOCs, while the age affects the deposition rates of CH2O, CH5N and C2H4O2. Positive correlation analysis between lung function factors and deposition rates revealed that the individuals with larger lung function factors are more susceptible to deposit the VOCs. Overall, the main conclusion can be drawn that the respiratory deposition rates were influenced by the physiological factors. Therefore, the major objective for future research is to accurately calculate the deposition rates of environmental VOCs for health-risk assessment.