Polybenzoapyrene

Polybenzo[a]pyrene is a term used for a subset of polycyclic aromatic hydrocarbons (PAHs) that share a benzo[a]pyrene-like fused-ring structure, with benzo[a]pyrene (BaP) as a prominent and well-studied member. BaP is a five-ring PAH and serves as a reference compound for assessing PAH-related risk. The broader group includes related PAHs that extend the core BaP structure by additional fused rings.

These compounds are formed during incomplete combustion of organic matter and are widespread environmental pollutants. Major sources include tobacco smoke, grilled or charred foods, vehicle exhaust, industrial emissions, and indoor and outdoor air pollution. Their physicochemical properties—high lipophilicity and environmental persistence—facilitate accumulation in soils, sediments, and living organisms, with potential transfer through the food chain.

Health effects of BaP and related polybenzo[a]pyrenes arise from their mutagenic and carcinogenic potential. Metabolic activation converts BaP into reactive diol epoxides that can form DNA adducts, potentially initiating mutations and cancer. BaP is classified by the IARC as a Group 1 carcinogen, with strongest human evidence for lung cancer from inhalation exposure, and associations with other cancers reported in observational studies.

Risk assessment often uses BaP as a marker for PAH exposure, employing toxicity equivalency factors to estimate the combined risk from mixtures. Monitoring methods include chromatography and fluorescence-based assays to quantify BaP and related PAHs in air, water, soil, and foods. Regulatory approaches aim to limit PAH emissions and reduce human exposure through dietary and environmental controls.