Revisiting the reaction of dicarbonyls in aerosol proxy solutions containing ammonia: the case of butenedial

Abstract. Reactions in aqueous solutions containing dicarbonyls (especially the α-dicarbonyls methylglyoxal, glyoxal, and biacetyl) reduced nitrogen (NHx) have been studied extensively. It has proposed that accretion reactions from NHx could be a source of particulate matter brown carbon atmosphere therefore direct implications for human health climate. Other dicarbonyls, such as 1,4-unsaturated dialdehyde butenedial, are also produced atmospheric oxidation volatile organic compounds, especially aromatics furans, but their aqueous-phase with not characterized. In this work, we determine pH-dependent mechanism butenedial is compared to α-dicarbonyls, particular glyoxal. Similar strongly hydrated solutions. Butenedial reaction produces nitrogen-containing rings leads form carbon. Despite glyoxal both being dialdehydes, observed three significant differences its chemical behavior: (1) previously shown, does substantially acetal oligomers, (2) butenedial/OH− light-absorbing (3) butenedial/NHx fast first order dialdehyde. Building off complementary study on gas-particle partitioning, suggest behavior other reactive dialdehydes may always adequately predicted by even though dominant functionalities closely related. The skeleton (e.g., hydrophobicity, length, bond structure) governs fate climate-relevant properties atmosphere. If behave like constitute regional