AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Rapid Oxidation of Skin Oil by Ozone
SHOUMING ZHOU, Matthew Forbes, Yasmine Katrib, Jonathan Abbatt, University of Toronto, Toronto, Canada
Abstract Number: 41 Working Group: Indoor Aerosols
Abstract One of the major recent findings in the field of indoor air chemistry is that human occupancy has significant impacts on indoor air pollution, mainly due to reactions of ozone with human surfaces such as skin oils. However, to date, there are no mass spectrometric studies of the chemical changes that occur in the condensed phase when skin oil is exposed to ozone.
In this work we investigated the reaction of human skin oil with ozone mixing ratios similar to those in the ambient environment. Using Direct Analysis in Real Time-Mass Spectrometry (DART-MS) skin oil gives rise to prominent mass spectral signals resulting from highly unsaturated alkenes (squalene), sterols, triglycerides, long chain fatty acids, pyroglutamic acid, and probably waxy esters. A rapid loss of squalene, fatty acids, and triglycerides was observed upon oxidation with 50 ppb ozone for 90 minutes, with the formation of highly oxygenated carboxylic acids, such as succinic acid, levulinic acid, adipic and suberic acids. One species, pyroglutamic acid, however, is found to be unreactive toward ozone. Therefore, this chemical may be used as a tracer of human contamination indoors.
This work demonstrates experimental evidence for rapid chemistry between skin oil and ozone, implying that the highly oxygenated reaction products are always present on human skin. Given earlier studies that have indicated the irritancy and redox-activity of squalene oxidation products, it will be important to further determine the toxicity of the condensed phase products from the multiphase reaction of ozone with skin oils.