A large range of observations have established that there is a significant downward trend in column ozone at middle latitudes in the northern hemisphere (NH) with most of the ozone depletion occurring in the lower stratosphere. Models largely underestimate this lower stratospheric ozone depletion. Recent one-dimensional model calculations <Lary et al., 1997> suggested that heterogeneous chemistry on black carbon could play a major role in stratospheric chemistry. Here, a two-dimensional aerosol/soot photochemical model is used to calculate the stratospheric global distribution of black carbon soot produced by aircraft emissions. The model-calculated distribution is found to be broadly consistent with observations <Blake and Kato, 1995>. By taking into account a catalytic heterogeneous reduction of O3 on aircraft-generated soot, the model is now able to reproduce a large part of the lower stratospheric ozone trend observed at NH middle latitudes. However, the results are sensitive to the assumed O3 uptake rate on soot which is still uncertain. Renoxification by the heterogeneous conversion of HNO3 into NOx on soot cannot account for most of the possible discrepancies between modeled and observed NOy partitioning because, similarly to the ozone uptake, its impact is mainly confined to the aircraft emissions region.¿ 1997 American Geophysical Union