Yields and Variability of Ozone Reaction Products from Human Skin

The skin of 20 human participants was exposed to similar to 110 ppb O-3 and volatile products of the resulting chemistry were quantified in real time. Yields (ppb product emitted/ppb ozone consumed) for 40 products were quantified. Major products of the primary reaction of ozone-squalene included 6-methyl 5-hepten-2-one (6-MHO) and geranyl acetone (GA) with average yields of 0.22 and 0.16, respectively. Other major products included decanal, methacrolein (or methyl vinyl ketone), nonanal, and butanal. Yields varied widely among participants; summed yields ranged from 0.33 to 0.93. The dynamic increase in emission rates during ozone exposure also varied among participants, possibly indicative of differences in the thickness of the skin lipid layer. Factor analysis indicates that much of the variability among participants is due to factors associated with the relative abundance of (1) fresh skin lipid constituents (such as squalene and fatty acids), (2) oxidized skin lipids, and (3) exogenous compounds. This last factor appears to be associated with the presence of oleic and linoleic acids and could be accounted for by uptake of cooking oils or personal care products to skin lipids.

Automated summary

The study found that ozone exposure resulted in the production of volatile products on human skin, with significant variations in product yields and emission rates among participants possibly due to differences in skin lipid layer thickness. Factor analysis suggests that variability among participants is mainly influenced by fresh skin lipid constituents, oxidized skin lipids, and exogenous compounds. The presence of oleic and linoleic acids, potentially from cooking oils or personal care products, also played a role in the observed variability.