Revealing the Origin of Polycyclic Aromatic Hydrocarbons in an Urban Snowpack

Polyciclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in urban atmosphere. Several PAHs are known carcinogens or are the precursors to carcinogenic daughter compounds. Understanding the contributions of various PAH emission sources is critical to appropriately managing PAH levels in the environment. The sources of PAHs to urban snowpack in Shelekhov city, Eastern Siberia, characterized by extremely high levels of PAH accumulation in snow were determined by using end-member mixing approach. The best potential to distinguish PAH emission sources is exhibited by ratios of PAH pairs of the principal mass 228, 252, and 276. The ratios of PAH pairs were used as tracers of end-member PAH sources. The contributions of sources were calculated using systems of linear equations. The results obtained using ratios of PAH pairs were compared with those obtained using molecular diagnostic ratios. It was shown that the results obtained using diagnostic ratios as tracers are less reliable than the results obtained using the ratios of the sums of PAHs.