Aerosol Generating Potential of the Products of Atmospheric Photooxidation of Biogenic Organic Compounds

Field measurements of the concentrations of oxygenated organics in urban air and in forest were carried out. The results were used to test the model of atmospheric transformation of biogenic compounds. The simulation showed that condensable compounds of several classes are formed: hydroperoxides, peroxides, alkylperoxynitrates and nitrites, peracids. Their aerosol-generating potential was evaluated on the basis of the calculated steady-state concentrations of the direct precursors of aerosol phase. It was discovered that the main precursors of the nuclei of solid phase are hydroperoxides and peracids. The reason of their efficiency is their photolysis with the formation of oxygenated free radicals, which initiate gas-to-particle conversion through polymerization of unsaturated compounds via the free radical mechanism.