Abstract: As an important component of atmospheric aerosols, organic aerosols have complex sources and transformation mechanisms. Threedimensional excitation emission matrix fluorescence spectroscopy (3D-EEM), featuring high sensitivity, convenience, and nondestructive analysis of sample structures, has been widely used in studies to understand the composition, sources, and transformation mechanisms of organic aerosols. By integrating fluorescence parameters with analytical approaches such as peak identification, fluorescence regional integration (FRI), and parallel factor analysis (PARAFAC), the 3D-EEM technique could effectively elucidate the chemical characteristics of fluorescent components across different solubility fractions and quantify chemical composition of aerosols from diverse sources. Moreover, 3D-EEM has also been combined with complementary techniques, such as ultraviolet-visible (UV-Vis) absorption spectroscopy, infrared spectroscopy, gas chromatography, and ultra-high-resolution mass spectrometry, to reveal the relationships between fluorescent chromophores, light absorption properties, and molecular structures of aerosols. To address those gaps, future efforts should prioritize the development of online 3D-EEM monitoring techniques, establish fluorescence parameter frameworks tailored to atmospheric conditions, expand the fluorescence characterization of fully dissolved components, and integrate machine learning to explore the correlations among fluorescence spectra, molecular compositions, and environmental effects. These efforts will further enhance the understanding of the source apportionment and environmental effects of organic aerosols, providing scientific insights for regional pollution control and climate model optimization.

Key words: atmospheric particle, fluorophore, chemical composition, source apportionment, mass spectrometry