A discussion of the chemistry of some minor constituents in the stratosphere and troposphere

Abstract

A discussion is given of atmospheric reactions in the H2O-CH4-O2-O3-NOx system. In the lower troposphere such reactions may lead to significant production of ozone. Their role in the odd hydrogen balance, especially of the troposphere and lower stratosphere, is discussed. CH3OH may be an intermediate in the oxidation cycle of methane, especially in the cold stratosphere. Its photodissociation into H2 and CH2O may consequently provide an important source for stratospheric H2. Catalytic photochemical chains of reactions involving NOx and HOx may also lead to tropospheric destruction of ozone. Due to lack of knowledge it is not possible at present to evaluate the importance of the before-mentioned reactions. With the aid of model calculations it is indicated that stratospheric ozone is most sensitive to changes in the adopted lower boundary values of N2O and that an increase in water vapour concentrations in the lower stratosphere will indeed cause some increase in ozone as predicted. Fluctuations in the flux of solar radiation near 190 nm may cause significant variations in stratospheric ozone concentrations. © 1973 Birkhäuser Verlag.