Recent determinations of O2absorption cross sections in the Herzberg continuum, obtained from in situ solar irradiance measurements, have shown that the corresponding laboratory values might be overestimated by 30 to 50 percent. The change in the stratospheric composition due to such a reduction in these cross sections has been calculated by means of a steady state one dimensional chemical model. An accurate determination of the O2absorption spectrum in the 200‐220 nm range is required since the distribution of several trace species is very sensitive to the atmospheric transmissivity in this wavelength regio