Modelling the impacts of aircraft traffic on the chemical composition of the upper troposphere

Abstract

Abstract

A three-dimensional chemistry-transport model has been used to assess the impacts of aircraft traffic in the upper troposphere. Aircraft engines emit NO_x, which has the potential to perturb the chemical composition at the flight altitude paths, i.e. at a 10–12 km height for subsonic flights. The model used includes a comprehensive chemistry scheme, so perturbations to other species apart from NO_x could also be examined. More specifically, the model showed that the monthly mean increase for NO_x due to aircraft is around 60 pptv (parts per trillion volume (30 per cent increase) and for HNO₃ it is 100 pptv (30 per cent increase). Consequently, O₃ is enhanced by 2500 pptv (5 per cent increase) due to aircraft traffic. To assess the regional and temporal variations in the perturbations, a time series analysis above a central European grid cell located at 47 °N 18 °E has also been performed. The analysis has indicated that the local perturbations can be much larger than the monthly mean values and can reach 200 pptv for NO_x, 150 pptv for HNO₃ and 5000 pptv for O₃.