Unveiling Condensed Aromatic Amines as Noteworthy Genotoxic Components in PM_2.5 Dissolved Organic Matter.

Area of Science:

• Environmental Chemistry
• Toxicology
• Molecular Epidemiology

Background:

• Particulate matter (PM_2.5) is linked to lung cancer, but specific causative agents within PM_2.5 remain unclear.
• Dissolved organic matter (DOM) is a complex fraction of PM_2.5 potentially containing harmful components.

Purpose of the Study:

• To identify and quantify genotoxic compounds within PM_2.5 DOM.
• To determine the sources and relative carcinogenic contribution of identified compounds.

Main Methods:

• High-resolution mass spectrometry (HRMS) for molecular characterization of PM_2.5 DOM.
• Cellular DNA damage assays and lung cell exposure models to assess genotoxicity.
• Regional source apportionment techniques.

Main Results:

• Hundreds of genotoxic compounds were identified, dominated by condensed aromatic amines.
• Norharman, a heterocyclic aromatic amine, was a key genotoxic component, with its genotoxicity relative to benzo[a]pyrene quantified.
• Carcinogenic compounds showed higher unsaturation, aromaticity, and nitrogen content compared to proinflammatory ones.
• Two-ring aromatic amines were significant contributors to both inflammation and genotoxicity.
• Significant regional variations in condensed aromatic amine concentrations were observed.

Conclusions:

• Condensed aromatic amines, particularly norharman, are significant genotoxic contributors in PM_2.5 DOM and warrant attention alongside PAHs in air quality management.
• Regional pollution profiles necessitate tailored mitigation strategies for PM_2.5-related health impacts.