Comparison of Atmospheric Monocarboxylic and Dicarboxylic Acids in Xi’ an, China, for Source Apportionment of Organic Aerosols

Photochemical Degradation of Organic Matter in the Atmosphere

“…Photochemical processes and primary emissions make dif ferent contributions to organic acids according to species, spatial, and temporal variations. Wu et al [61] demonstrate that monocarboxylic acids mainly comes from primary emissions including coal combustion and vehicle exhaust, while the sec ondary photochemistry and aqueousphase oxidation are the major sources of dicarboxylic acids in Xi′an, China. On hazy days, pollutants released from vehicle exhaust and cooking accumulated under the conditions of temperature inversion and high humidity, and provided enough precursors for pho tooxidation to form a high abundance of dicarboxylic acids.…”

“…On hazy days, pollutants released from vehicle exhaust and cooking accumulated under the conditions of temperature inversion and high humidity, and provided enough precursors for pho tooxidation to form a high abundance of dicarboxylic acids. [61] Zhao et al [50] suggest that the organic acids at the ground level were greatly related to local traffic emissions, whereas the long distance transport followed by atmospheric photochemical aging contributed greater to dicarboxylic acids and related com pounds in the atmospheric boundary layer than the ground surface in urban Beijing. Hoque et al [62] demonstrated that atmospheric levels of watersoluble organic aerosols including dicarboxylic acids and related compounds in the eastern North Pacific are significantly dependent on primary productivity fol lowed by seatoair releases of isoprene and unsaturated fatty acids and the subsequent photochemical oxidation.…”

Impact of acidity and surface-modulated acid dissociation on cloud response to organic aerosol

“…Organic aerosols contain a substantial fraction of species exhibiting Brönsted acid character (Jacob, 1986;Millet et al, 2015;Keene and Galloway, 1984;Chebbi and Carlier, 1996;Chen et al, 2021b;Angelis et al, 2012;Mochizuki et al, 2016;Wu et al, 2020;Kawamura et al, 1985). The concentrations of acidic species in aqueous aerosols directly affect the aerosol pH by modifying the H + concentrations within the aerosol (Pye et al, 2020;Ault, 2020).…”