THE EFFECT OF AIRCRAFT EMISSIONS ON TROPOSPHERIC OZONE IN THE NORTHERN-HEMISPHERE

The effect of aircraft emissions on tropospheric ozone was studied using a two-dimensional zonal model, of longitude vs altitude, extending between 30-degrees-60-degrees-N. An emission inventory for the 1987 civil aircraft fleet was constructed based on fuel usage and civil aviation statistics. The addition of the 1987 civil emissions to a modelled standard atmosphere caused increases in concentrations of O3 (12%; 10 ppbv), NOx (40%; 20 pptv) and OH (10%) between 8 and 12 km altitude. A doubling and tripling of the emissions corresponding to a present day inclusion of military aircraft and a future scenario, respectively, caused the increase in O3 to double (19%) and almost triple (25%). The lightning source of NOx was found to be an important parameter. When this source was omitted the change in O3 at the cruise flight altitude increased to 16%, with respect to a standard atmosphere not containing a lightning source of NO(x).