Lichen exometabolites as possible precursors of secondary organic aerosols
M.P. Tentyukov1,2, B.D. Belan1, D.V. Simonenkov1, S.A. Patov3, V.I. Mikhailov3, G.V. Simonova4, S.N. Plyusnin2, Yu.A. Bobrov2
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
2Pitirim Sorokin Syktyvkar state University, Syktyvkar, Russia
3Institute of Chemistry of the Komi Science Centre of the Ural Division RAS, Syktyvkar, Russia
4Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences, Tomsk, Russia
Keywords: aerosols, delta15N, delta13C, volatile organic compounds, lichen acids, chromatographic analysis, phenols, exometabolites, epiphytic lichens
Abstract
Lichens are not only a bioindicator of air pollution, but they themselves, in turn, affect the chemical composition of the air. The results of studies of the qualitative composition of exometabolites in thalli of epiphytic lichens using the method of high-performance liquid chromatography are presented. A comparative analysis of the fractional composition of deposited aerosol matter in water washouts of lichens showed that it is characterized by a bimodal type of particle distribution. It is postulated that the appearance of the fine fraction is associated with the formation of secondary organic aerosols on the surface of epiphytic lichens. Their precursors are the products of photoactivated reactions between deposited aerosol matter and highly volatile organic compounds that arrive on the surface of lichens as a result of efflorescence. The mechanism of entry of secondary organic aerosols into the surface atmosphere under the influence of radiometric photophoresis is discussed.
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