Polycyclic aromatic hydrocarbons (PAHs) represent a class of ubiquitously occurring environmental compounds that are implicated in a wide range of toxicological effects. Routine measurement of PAH contamination generally involves chemical analytical analysis of a selected group of representatives, for example, EPA-16, which may result in an underestimation of the PAH-related toxicity of a sample. Many high molecular weight PAHs are known ligands of the aryl hydrocarbon receptor (AhR), a nuclear receptor that mediates toxic effects related to these compounds. PAH CALUX is a bioassay for the identification of total PAH mixtures. The PAH CALUX has a 4 h exposure time and quantification of AhR-induced luciferase induction can be made relative to benzo[a]pyrene (BaP).