Answer
There is no mercury in airplane fuel.the eia classifies jet fuel into two categories: "naphtha-based" and "kerosene-based." kerosene-based jet fuel includes civil-grade jet a, consumed in commercial jet airliners, which is an important contributor to u.s. greenhouse gas emissions and accounts for more than 4 percent of u.s. carbon dioxide emissions. naphtha-based jet fuels were used primarily by the military until 1993, when the u.s. department of defense began a conversion from naphtha-based jp-4 jet fuel to kerosene-based jp-8 jet fuel. as a result, the share of naphtha-based jet fuel has declined from 12 percent of u.s. jet fuel consumption in 1991, to 7.2 percent in 1993,to 0.3 percent in 1996.(199) the annual emissions coefficients for jet fuel are consumption-weighted averages of the coefficients for kerosene-based and naphtha-based jet fuels (table b4). because the emissions coefficient for naphtha-based jet fuel is about 3 percent higher than the coefficient for kerosene-based jet fuel, the near elimination of naphtha-based fuels has led to a steadily declining emissions coefficient. in 1996, naphtha-based jet fuel consumption dropped to the point at which it no longer has a significant impact on the weighted average computation. hence, the 1996 weighted-average emissions coefficient is equal to the coefficient for kerosene-based jet fuel (to the second decimal place).