<title>Photoacoustic trace gas detection of ethene released by UV-induced lipid peroxidation in humans</title>

Abstract

A sensitive CO<SUB>2</SUB> laser-based photoacoustic (PA) detector has been used to perform non-invasive and on-line measurements of ethene (C<SUB>2</SUB>H<SUB>4</SUB>) production from exhaled air and directly emitted from the skin. Ethene was used as indicator for free- radicals induced lipid peroxidation in the skin of human subjects exposed to ultraviolet (UV) radiation from a solarium. Ethene from the exhaled air was analyzed for a group of 21 male subjects at rest. During 15 minutes of UV exposure, the average ethene emission was 17.2 pmol/kg/min (SD 7.3), while the pre-UV exposure levels were 1.4 pmol/kg/min (SD 0.38). Different types of sun protection creams were tested by means of ethene release in exhaled air. The influence of UV radiation intensity and of exposure time (10 and 15 minutes, respectively) on the ethene emission from the skin has been studied for a second group of 12 subjects. Comparison between measurements of exhaled air and directly on the skin is presented.