What are the 16 PAHs?

Understanding the 16 Priority PAHs

Polycyclic Aromatic Hydrocarbons, commonly known as PAHs, are a group of organic compounds formed during the incomplete burning of coal, oil, gas, wood, and garbage. While hundreds of individual PAHs exist in nature and industrial emissions, environmental regulatory agencies like the US EPA focus primarily on a standard set of 16 priority PAHs for risk assessment and monitoring.

This specific list was chosen because these compounds appear most frequently in environmental soil, water, and air samples. The group includes lighter, lower molecular weight molecules such as naphthalene, acenaphthene, acenaphthylene, fluorene, anthracene, fluoranthene, phenanthrene, and pyrene. It also features heavier, complex structures—several of which are known or suspected carcinogens—including benzo[a]pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, and dibenz[a,h]anthracene.

Tracking these 16 baseline pollutants allows scientists and environmental agencies to reliably measure overall contamination levels and evaluate potential risks to public health and local ecosystems.