Migration mechanism of PAH4 into cooking fume particles during frying: Driving role of lipid oxidation and the carrier effect of carbonyl compounds.

The cooking fumes from frying carry highly toxic polycyclic aromatic hydrocarbons (PAHs), which pose a serious threat to human health. This study utilized the stable isotope PAH4-d12 to simulate the migration of PAH4 from frying oil into cooking fumes, and characterized the process through physicochemical analysis of oils, single particle aerosol mass spectrometry, GC-MS, and quantum chemical calculations. The results indicate that the concentration of PAH4-d12 in cooking fumes increases linearly with cooking time, and that it accumulates preferentially in fine particles with an aerodynamic diameter of less than 1.1 μm. The migration of PAH4-d12 increases significantly with the degree of lipid oxidation. The radical-mediated oxidation of unsaturated fatty acids is the key driving force behind PAH4 migration. The abundance of oxygen-containing functional groups on the surface of cooking fume particles further enhances the carrier capacity. Carbonyl compounds are key components responsible for carrying PAH4, their binding to PAH4 is primarily governed by intermolecular van der Waals forces, while the strength of π-π stacking and C-H-π interactions depends on the structure. These findings reveal that lipid oxidation and particle properties jointly regulate the migration of PAHs, and provide insights at molecular level for pollution control.