Changes in tropospheric NOx and O3 due to subsonic aircraft emissions

Model studies using two-dimensional models have shown that near the tropopause aircraft NOx emissions can lead to ozone production, whereas they can lead to ozone depletion in the middle atmosphere. They could have an important impact on the atmospheric composition.The sensivity to NOx emissions by lightning is investigated, since its magnitude is still very uncertain. They may range from about 1 up to 100 times the NOx emissions by aviation for the 1990 scenario.