The Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine has released an FAA-sponsored report on the air quality impact of sustainable alternative jet fuel (SAJF) emissions. SAJFs, or “biofuels,” are synthetically-made fuels intended to reduce carbon dioxide emissions of aircraft that can be used within the existing U.S. fuel distribution system and without making engine modifications. Another main purpose of using SAJFs is to reduce pollutants such as carbon monoxide, sulfur dioxide, nitrogen oxide, soot, and unburnt hydrocarbons, among others.
“Until this report, these reductions had not been well defined,” said co-author Dr. Phillip Whitehead, professor and chair of chemistry at the Missouri University of Science and Technology, and director of the Center for Research in Energy and the Environment. “Airlines are also constrained by emission limits set by the EPA and must make sure that by using SAJFs, they will not receive fines.”
The report shows that when blended with conventional jet fuels according to ASTM standards, the SAJFs significantly reduce sulfur dioxide and soot, generally reduce carbon monoxide and unburnt hydrocarbon emissions, and have minimal effect on nitrogen oxide emissions.
Based on the review of 51 separate emissions analyses, Whitehead noted, “All evidence suggests that the use of SAJFs will substantiate reductions in pollutant emissions.”