Chemical Composition and Reaction Mechanisms for Aged p-Xylene Secondary Organic Aerosol in the Presence of Ammonia: Composition and Mechanisms for NH3-aged SOA

NH 3 has a significant promotional effect on the formation of organonitrogen compounds in aged aromatic secondary organic aerosol (SOA) in the presence of NO. Ammonium carboxylates formed from NH 3 reactions with organic acids and imidazole compounds via the heterogeneous reactions between NH 3 and dialdehydes of SOA are the major particulate organonitrogen products. Our results suggest that some ambient particles containing organonitrogen compounds may be arising out of this mechanism.