Atmospheric Degradation of Amines (ADA). Summary report: Photo-oxidation of methylamine, dimethylamine and trimethylamine. CLIMIT project no. 201604.

The atmospheric gas phase photo-oxidation of methylamine (CH3NH2), dimethylamine ((CH3)2NH) and trimethylamine ((CH3)3N) has been studied under pseudo natural conditions at the European Photochemical Reactor, EUPHORE, in Valencia, Spain. Major products in the photo-oxidation were imines (methanimine and N-methyl-methanimine) and amides (formamide, N-methyl formamide and N,N-dimethyl formamide). Total aerosol yields obtained in EUPHORE experiments were between 8 and 14%. Mimicking conditions at Mongstad results in a steady-state nitrosamine concentration of less than 0.6 % of photo-oxidized dimethylamine and less than 1.1 % of photo-oxidized trimethylamine. For rural regions it is predicted that the formation yield of the corresponding nitramine in the atmospheric oxidation of CH3NH2, (CH3)2NH and (CH3)3N is less than 0.4 %, 2.5 % and 5 %, respectively. The major uncertainties in the current understanding of the fate of amines emitted to the atmosphere are related to night-time chemistry, to the chemistry of imines, and to chemistry in the aqueous aerosol.