Introduction: Tobacco smoke is one of the most common air pollutants found in the indoor environment. Passive smoking is defined as the involuntary inhalation of tobacco smoke present in the air. This article examines the advantages and limitations of the methods that are available to measure environmental tobacco smoke exposure.
State of the art: Passive smoking can be assessed either by measuring tobacco smoke pollutants found in the air directly or by using biomarker assays, an indirect measure of exposure.
Conclusion: As far as the direct measurement of air pollutants is concerned, nicotine and 3-Ethenylpyridine levels seem most suitable because of their specificity. Four specific biological markers of tobacco smoke exposure are available: nicotine, cotinine, thiocyanates, and protein or DNA adducts. Only urinary cotinine assay can be retained as a reliable marker of exposure to tobacco smoke. It has been used as a reference in most epidemiological studies but only reflects tobacco exposure over the preceding 48 hours. The measurement of nicotine and cotinine levels in the appendages of the skin (hair and nails) reflects exposure to tobacco over the previous three months and could become a better reference marker in epidemiological and toxicological studies.