Carbonaceous aerosol in jet engine exhaust:: emission characteristics and implications for heterogeneous chemical reactions

Characteristic parameters of black carbon aerosol (BC) emitted from jet engine were measured during ground tests and in-flight behind the same aircraft. Size distribution features were a primary BC mode at a modal diameter D approximate to 0.045 mu m, and a BC agglomeration mode at D < 0.2 mu m. The total BC number concentration at the engine exit was 2.9 x 10(7) cm(-3) with good agreement between model results and in-flight measured number concentrations of non volatile particles with D greater than or equal to 0.014 mu m. A comparison between total number concentration of BC particles and the non-volatile fraction of the total aerosol at the exit plane suggests that the non-volatile fraction of jet engine exhaust aerosol consists almost completely of BC. In-flight BC mass emission indices ranged from 0.11 to 0.15 g BC (kg fuel)(-1). The measured in-flight particle emission value was 1.75 +/- 0.15 x 10(15) kg(-1) with corresponding ground test values of 1.0-8.7 x 10(14) kg (-1). Both size distribution properties and mass emission indices can be scaled from ground test to in-flight conditions. Implications for atmospheric BC loading, BC and cirrus interaction and the potential of BC for perturbation of atmospheric chemistry are briefly outlined. (C) 1999 Elsevier Science Ltd. All rights reserved.