Formation of pollution particulate nitrogen compounds by NO-soot and NH 3-soot gas-particle surface reactions
Three reduced forms of nitrogen are associated with ambient air pollution particulates: ammonium and two additional species assigned to amine and/or amide and to nitrile. Nitrogen species of the same type and behavior can be synthesized in soot (or graphite) interactions with NO or NH 3. Volatile hydroxyl and carboxyl ammonium salts (and/or physically adsorbed ammonia species) are produced in soot-NO and soot-NH 3 reactions at ambient temperatures, while amines, amides and nitriles are produced at higher temperatures. The proposed mechanism is in qualitative agreement with the field observations. The experiments were performed with the aid of X-ray photoelectron spectroscopy, ESCA.