Aircraft emissions in the form of condensation trails — contrails — likely contribute to global radiative forcing at a level roughly equivalent to that of carbon dioxide emissions from the entire aviation sector, which is estimated to be about 2% of total global CO₂ emissions. Recent research indicates that naphthalenes in petroleum jet fuel account for a disproportionately large share of the particulate matter in engine exhaust and are a major component in contrail formation.

Opportunities to cost-effectively remove these aromatics from jet fuel via hydrotreating and extractive distillation were the focus of an assessment conducted by MathPro Inc. for the International Council on Clean Transportation.

Hydrotreating, a process widely used in the refining industry, would remove the naphthalenes by converting them to other aromatics and other hydrocarbons. Extractive distillation would also remove naphthalenes by employing a solvent to extract virtually all the aromatics and naphthalenes from the straight run kerosene stream. The extracted aromatics would be separated from the naphthalenes and sent to the petroleum jet fuel pool.

The most cost-effective route for conversion refineries is determined to be hydrotreating. An incremental cost of $0.09 to $0.12 U.S./gallon to hydrotreat fossil jet fuel at facilities that produce the bulk of aviation jet fuel worldwide is estimated. This incremental cost represents a 4% to 5% increase from current jet fuel prices, compared to the two- to five-times cost premium typically quoted for sustainable aviation fuels.