Polycyclic aromatic hydrocarbons (PAHs) should be treated differently than routine environmental contaminants when measured as part of your environmental investigation.  They present with distinctive fingerprints from their sources and move together in the environment as a family of compounds.  Therefore, all environmental investigations measuring PAHs should take the time to interpret the PAH results and not simply tabulate the data and compare them to regulatory standards.  This presentation will describe some fundamentals of PAHs and PAH fingerprints as well as demonstrate how they can be used to help your environmental investigations.