Urban greening as a factor of environmental stability: the role of trees in decreasing aerosol formation during photonucleation of industrial emissions
G.G. Dultseva1,2, S.N. Dubtsov1,2
1V.V. Voevodsky Institute of Chemical Kinetics and Combustion of the Siberian Branch of the RAS, Novosibirsk, Russia
2Institute of Computational Mathematics and Mathematical Geophysics of the Siberian Branch of the RAS, Novosibirsk, Russia
Keywords: atmospheric organic aerosol, biogenic aldehyde, formaldehyde, tree planting, simulation
Abstract
The role of vegetation in atmospheric chemistry is not limited to carbon dioxide absorption and oxygen evolution during photosynthesis. It is known that plant-emitted organic compounds (alkenes and aldehydes) participate in the generation of atmospheric aerosol. However, the mechanisms of related processes have been studied in detail only for alkenes. Our work assesses the effect of urban trees on air quality for the case of Novosibirsk. Tree species characterized by stability against urban air pollutants (nitrogen oxides, ozone, organic peroxides, and acids) were revealed, biochemical markers providing the stability of these species were determined, and the composition of volatile organic compounds emitted by these species was studied. Under laboratory conditions, the aerosol-forming ability of these compounds was studied, the mechanisms of their photooxidation were determined, and the yield of aerosol products was measured. For some species (aspen, birch, linden, poplar, and maple) used for greening in Siberian cities, the ability to absorb gaseous pollutants, such as formaldehyde, formic acid, and organic peroxides, has been discovered. On the basis of the data on absorption and emission of aerosol-forming components by trees, the contribution from urban green zones into the chemistry of organic aerosol was evaluated. It is shown that targeted greening of the cities with gas-absorbing tree species can reduce the aerosol load on residential areas by no less than 20-30%.
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