Screening of Cytotoxic Semi-volatile Organic Components (SVOCs) of PM2.5 with an Omics Approach

The semi-volatile organic components (SVOC_S) are the most complex components of atmospheric fine particles, but the health hazards of specific substances of most organic species are still unclear. In this study, the mouse alveolar macrophages were used as a model to analyze the untargeted signals of semi-volatile organic compounds in the organic extracts of fine-particle samples in Beijing during a 1-year period by gas chromatography-time of flight mass spectrometry (GC-TOF). Indicators of cytotoxic effects of organic extracts on the mouse macrophages were analyzed, including levels of intracellular reactive oxygen species (ROS) and extracellular secretion of inflammatory factors such as IL-1β, IL-6 and TNF-α, to identify key toxic components in fine particles and its differences between different toxic effects. The study found that the organic components in atmospheric fine particles on different toxicity indicators are mainly affected by the types or sources of organic components. Oxygenated polycyclic aromatic hydrocarbons are significantly associated with IL-1β, IL-6, TNF-α, and have many strongly effective species; methyl polycyclic aromatic hydrocarbons and hopanes are mainly related to IL-1β, and have weak relation with other indicators. PAHs have weak relationship with IL-1β，IL-6 and TNF-α. The above species are not closely related to ROS. Positive matrix factorization analysis (PMF) found four sources, namely coal combustion, biomass burning, vehicle exhausts and secondary formation. Coal combustion and biomass burning are the main sources to the oxygenated PAHs, methyl PAHs and PAHs (>80%). Hopanes are mainly derived from vehicle exhausts. The secondary formation contributed significantly to the oxygenated PAHs, and two of oxygenated PAHs (1,8-Naphthalic anhydride and 9,10-Anthraquinone) are mainly derived from secondary formation.