 Phenanthrols are any of five isomeric phenols derived from phenanthrene (1-phenanthrol, 2-phenanthrol, 3-phenanthrol, 4-phenanthrol, 9-phenanthrol).These molecules can be biomarkers of smoking and/or PAH worker exposure.Under UV irradiation, stilbene and its derivatives undergo intramolecular cyclization to form dihydrophenanthrenes.