Inflammation plays a central role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Monitoring of inflammation of the airways has, therefore, become a growing are of research and there is particular interest in noninvasive approaches which allow frequent monitoring. Induced sputum has provided important insights into airway inflammation in COPD. However, induced sputum is relatively invasive. This has focused attention on other noninvasive methods. Exhaled breath condensate has the potential to measure semi-volatile lipid mediators. However, a major problem limiting the usefulness of this technique is variable dilution with water vapor and low concentrations of mediators. Many volatile organic compounds have been detected in the breath and the pattern of molecules can now be characterized with various electronic noses.