Comprehensive Characterization of Organic Chemicals Associated with Urban Particulate Matter in China

Atmospheric particulate matter (PM) is considered a health hazard; however, the inadequate identification of the components of PM limits our understanding of its specific toxic pollutants. Herein, by combining three extraction solvents with different polarities (dichloromethane, hexane, and acetonitrile) and three ionization modes (electron ionization and the positive and negative modes of electrospray ionization), we comprehensively analyzed the organic chemicals in the PM_2.5 and PM₁₀ samples collected during summer and winter in Beijing. Suspect screening was facilitated by comparison with the mzCloud and the National Institute of Standards and Technology databases for tentatively characterizing chemical identities. Results showed that more compounds were identified in the winter PM_2.5/PM₁₀ samples than in the summer samples and that PM_2.5 contained a greater number of chemicals than PM₁₀. Based on peak areas of compounds, the predominant pollutants in the winter PM_2.5/PM₁₀ samples were phenols, amines, and aromatic compounds; however, significantly high responses of one phenol and two ester compounds were detected in the summer PM_2.5/PM₁₀ samples. Based on the Tox21 toxicological database, a total of 60 identified pollutants were associated with 28 biological targets, and ∼50% of the active compounds were phenolic and aromatic compounds. The biological targets most affected by these pollutants were related to metabolic homeostasis, reproduction, and developmental functions. This study underscores the importance of a multiapproach analysis in comprehensively identifying environmental pollutants and highlights the potential health risks posed by PM.