Influence of Particles of the Junge Layer on the Rate of Ozone Destruction in the Lower Stratosphere

Abstract

The paper presents the results of calculations of the dynamics of ozone destruction in the lower stratosphere, carried out taking into account the heterogeneous chemical reactions (HCRs) proceeding at a rate of w(–O₃)_HCRs, cm^–3 s^–1, with the participation of particles of the Junge layer (background aerosol). The dramatic decline in w(–O₃)_HCRs found in the calculations at altitudes less than 16 km in comparison with the rate of ozone loss calculated with the participation of gaseous chemical reactions (w(–O₃)) indicates the inhibitory role of aerosol particles. This is due to the capture of N₂O₅ molecules from the air by aerosol particles. Their rapid runoff entails a sharp decrease in the concentrations of components of the NO_x family in air, as well as a less pronounced decrease in the concentrations of components of the HO_x, and O_x families involved in the destruction of ozone. At higher altitudes of 16 to 22 km, magnitude w(–O₃)_HCRs, in contrast, turns out to be slightly higher than w(–O₃); and it affects the acceleration of the destruction process with the components of the HO_x and ClO_x families. The increased level of their concentrations and rates of reactions with ozone is due to the reduced content of the components of the NO_x family in the air. This positive effect of the HCRs involving aerosol particles in w(–O₃)_HCRs practically degenerates, but at even higher altitudes. This is due to the decrease in the content of aerosol particles and the acceleration of the photodissociation of molecules N₂O_5(g) $\xrightarrow{{h{{\nu }}}}$ NO_3(g) + NO_2(g), which on the whole is accompanied by the suppression of the process of their capture by particles.