Research within in the field of airway and lung inflammation has expanded tremendously during recent decades. Attempts are continuously being made to find novel methods to mirror and monitor inflammatory reactions related to airway disorders and dysfunction. The lungs are particularly well suited for this purpose as we have easy access to exhaled air and thereby a possibility to develop methods that measure compounds directly released from them.

As this area of interest is rather new this is the first issue of the European Respiratory Monograph to focus on inflammatory markers. As this field is rapidly expanding it was decided, after some initial discussions, to limit this Monograph to markers in exhaled air and to produce a comprehensive update of the entire field.