Abstract: In this study, we summarized the seasonal variation, molecular distribution of low molecular weight (LMW) dicarboxylic acids, oxocarboxylic acids and α-dicarbonyls in atmospheric aerosols, and also discussed the experimental methods, photochemical aging, size distributions, sources, and transformation processes as well as diagnostic ratios of these organic acids. Based on the analyses and comparisons of dicarboxylic acids and related compounds in urban, marine and polar areas, we suggested that continental aerosols were mainly associated with anthropogenic emissions, such as fossil fuel combustion, biomass burning, meal cooking and plastic waste burning; whereas marine aerosols were not only affected by outflows from continental areas, biogenic unsaturated fatty acids and biogenic semi-volatile organics emitted from the surface ocean, but also attributed to the photochemical oxidation of related precursors during the long-range atmospheric transport. In addition, we discussed the compound specific stable carbon isotopic analyses of diacids, oxoacids and α-dicarbonyls. The isotopic composition of diacids was a powerful tool to investigate the photochemical aging processes of atmospheric aerosols. At last, the relationship between the longdistance transport of aerosol and the stable carbon isotope composition of diacids and related compounds was also illustrated in this paper.

Key words: photosynthetic nitrogen use efficiency, nitrogen allocation fraction, CO₂ diffusion conductance, Betula utilis, altitude