Jet engine exhaust aerosol characterization

Jet engine exhaust aerosol was characterized with respect to mass concentration and composition of the carbonaceous aerosol fraction and the particulate sulfate as a function of engine power setting for fuel with low-sulfur content 16 ppm) and high-sulfur content (3000 ppm). The ratio of black carbon (BC) to total carbon (TC varied from 11% with the engine in idle run to >80% at take-off thrust. The corresponding BC emission index was <0.6 g kg(-1) fuel on a mass scale and <1.7 x 10(15) kg(-1) fuel on a number scale. The optical specific absorption coefficient of the BC aerosol was measured to 6 +/- 1 m(2) g(-1) by filter reflectance analysis (lambda approximate to 0.8 mu m). The carbon aerosol split into a primary soot mode at 0.045 mu m diameter with geometric standard deviation 1.5 and a coagulation mode at 0.18 mu m diameter with geometric standard deviation 1.32. The mass emission index of particulate sulfate remained almost constant at <0.05 g kg(-1) throughout the examined engine power setting between 11% and 71% take-off thrust. The conversion rate from SO2 molecules into particulate SO42- within the young exhaust plume prior to sampling (plume age <0.1 s) was <0.5% with only a slight dependence on engine power setting. (C) 1998 American Association for Aerosol Research.