In a typical collection, after normal exhalation, the subject will breath through a mouthpiece a filtered air to remove all VOCs of any ambient contaminants. Individuals will exhale in a constant flow rate. The exhaled air will be contained through the mouthpiece by Mayler bags and/or will be passed through a container. The collected air breath samples will be analysed for VOC by gas-chromatography mass spectrometry (GC-MS), highly-sensitive nano-sensors (Nanomaterial-Based Devices, Technion - Israel Institute of Technology, Haifa, Israel) or as online mass spectrometry (Ionimed, Austria). Further, the signals will be analyzed by a pattern recognition algorithms, such as principal component analysis (PCA), supported vector machines (SVM), or neuronal network analysis can then be applied on the entire set of signals to acquire information on the identity, properties and chemical composition of the vapor exposed to the sensors array 5, 10.