Intergovernmental Panel On Climate Change / IPCC
Aerosol Emission and Formation in Aircraft Plumes
Aircraft jet engines directly emit aerosol particles and condensable gases such as water vapor (H2O), sulfuric acid
(H2SO4), and organic compounds, which lead to the formation of new, liquid (volatile) particles in the early plume
by gas-to-particle conversion (nucleation) processes. Other gas-phase species and charged molecular clusters
(chemi-ions, or CIs) are also generated at emission, including nitric acid (HNO3) and nitrous acid (HNO2). Emission
and formation of H2SO4 depend on fuel sulfur content, or sulfur emission index [EI(S)], and the conversion fraction
of fuel sulfur to H2SO4.