Regional and Whole-Body Dermal Emission Rates of Volatile Sulfur Compounds and Potential Impact on Indoor Air Odour

Volatile sulfur compounds (VSCs) are known to cause characteristic—and sometimes unpleasant—body odour. Human presence may influence the odour of indoor air; however, the contribution of skin-derived VSCs has not been thoroughly evaluated. This study aimed to elucidate the regional and whole-body dermal emission rates of VSCs—diallyl disulfide (DADS), allyl methyl sulfide (AMS), ethyl mercaptan (EMT), allyl mercaptan (AMT) and dimethyl trisulfide (DMTS)—by conducting simultaneous and multi-point measurements of dermal emissions from the human skin surface to assess their potential impact on indoor air quality. Dermal emission fluxes of VSCs were measured at 14 anatomical regions of 12 healthy young subjects using a passive flux sampler coupled with gas chromatography/mass spectrometry. These fluxes were converted to emission rates using regional body surface area, and the whole-body emission rates were subsequently used to estimate indoor air concentrations for comparison with the odour thresholds of each VSC. The results showed that although some regional differences in emission rates were observed among subjects, the large inter-individual variability ultimately led to no significant differences in whole-body emission rates of VSCs between males and females. Using the average whole-body emission rates across 12 subjects, the estimated indoor air concentrations of VSCs followed the descending order: EMT > AMT >> DMTS > AMS > DADS. The odour quotient was used to evaluate the impact of skin-derived VSCs on indoor air quality and indicated that EMT consistently contributes to indoor odour.