The existence of many different sources of nicotine, 3-ethenylpyridine, benzene, and xylenes, other than tobacco smoke has limited their efficiency as appropriate markers for environmental tobacco smoke (ETS).

However, Juan Sanchez and co-workers, University of Girona, Spain, report that 2,5-dimethylfuran uniquely signals the presence of cigarette smoke. This compound was not detected in outdoor environments, ruling out any association with traffic emissions. It was only detected in one of 15 nonsmoking indoor environments as opposed to 39 of the 41 smoking indoor environments evaluated.

2,5-Dimethylfuran could also be used as a smoking breath biomarker as it was continuously detected in the breath of nonsmoking employees after being in direct contact with ETS for just a few hours. Accurate detection of second-hand smoke in working environments could help minimize exposure and the attendant health risks.

• Assessment of Environmental Tobacco Smoke Contamination in Public Premises: Significance of 2,5-Dimethylfuran as an Effective Marker
  M. Alonso, A. Godayol, E. Antic, J. M. Sanchez,
  Environ. Sci. Technol. 2010, 44.
  DOI: 10.1021/es1016075