Organic aerosols are a major component of PM_2.5 and have a direct impact on the environment and human health due to their abundance in the ambient environment and complex physical and chemical properties. For this reason, it is highly important to detect organic compounds in the atmosphere and identify their source.

In this study, the PM_2.5 filter samples were collected in the Seoul, Beijing and Ulaanbaatar in 2020-2021 winter for a month. The organic extracts from PM_2.5 were analyzed using two-dimensional gas chromatography/high resolution time-of-flight mass spectrometry (GCxGC/HRMS). A qualitative analysis was performed with high accuracy (<5 ppm) on PAHs and n-alkanes in a complex compounds using a library search. In addition, we confirmed source identification and risk assessment based on quantitative data with primary PAHs as standard substances.

The results showed more and higher concentration of PAHs in Ulaanbaatar rather than in beijing and seoul. Using PAH concentration, it was possible to compare the harmfulness of PM_2.5 between three cities as toxic equivalency factor. In addition, all analytes were classified as one of six chemical groups to confirm cross-country interactions. The source material for generating PM_2.5 was identified using the number of aromatic rings and the specific PAHs.