PAHs (Polycyclic Aromatic Hydrocarbons), refer to hydrocarbons containing two or more benzene rings connected together in the molecule. To date, more than 200 types of PAHs have been discovered. PAHs are a class of harmful substances produced under conditions of incomplete combustion or high-temperature treatment of fuels such as petroleum, coal, and wood, as well as combustible gases. They are commonly found in petrochemical products, rubber, plastics, lubricants, rust-proof oil, and incompletely combusted organic compounds, and are one of the important carcinogens in the environment. Various regulations, including the EU REACH regulation, German GS mark certification, and California Proposition 65, have put forward control requirements for PAHs. You can refer to the introduction of CTI: https://www.cti-cert.com/service/3130/5330.html