The formation of organic particulate matter (OPM) in the atmosphere is influenced by gas/particle partitioning of low-volatility compounds, including products of volatile organic compound oxidation. Secondary reactions among these products, known as accretion reactions, can generate high–molecular weight species that enhance particle formation. This study evaluates the thermodynamic favorability of various accretion pathways and their potential contribution to OPM. Results indicate that accretion reactions involving small aldehydes and ketones are generally unfavorable, whereas processes such as aldol condensation of larger aldehydes, reactions of glyoxal and methylglyoxal, and formation of esters and amides from carboxylic acids are thermodynamically favorable and may significantly contribute to atmospheric OPM formation.
