Breath analysis is a non-invasive tool that can be used to measure body impact following exposure to air pollutants. A method for collecting and analyzing exhaled breath was developed and used to compare individual exhaled breath volatile organic compounds (VOCs) with ambient air VOCs. Exhaled breath was collected in Teflon bags and analyzed using thermal desorption gas chromatography -mass spectrometry. The repeatability of this method was examined following analysis of 10 breath samples of each of three subjects. An environmental health study including 56 3-year-old children in Flanders examined abundances of VOCs in exhaled breath in relation to the presence of these VOCs in ambient air. It was demonstrated that a number of VOCs were either significantly retained or cleared by the body.