Jet engines are a source of gaseous and particulate emissions being released into the atmosphere. The number of species emitted by jet engines depends on the kind of fuel and the design of the jet engine. However, because the emissions of aircraft engines occur in the atmospheric regions (high troposphere and low stratosphere), which are very sensible to various perturbations, the problem of aviation effect on atmospheric processes and climate change has become very important.
Particulates when released into the environment are harmful. Particulates in engine exhaust form because of incomplete combustion of the fuel within the combustion chamber of the jet engine. Thus, particulate emissions are higher at low engine powers because combustion efficiency is lower. Particulate emissions from jet engines are highest at take-off and climb-out operations that require very high fuel flow rates. Therefore, data would be expected to show high particulate emissions around airports. Aerial depositions of exhaust particles from air traffic may have impacts on human health and the environment. High levels of ambient particulate matter have been found to adversely affect human respiratory systems, causing the development of asthma, lung cancer, and chronic bronchitis, among other problems.
Unlike internal combustion engines, particularly diesel engines where particulate filters are often employed to attempt to abate these particulate matter emissions, there is no known technology for reducing particulate matter emissions for jet engines. The best way to reduce particulate matter emissions in jet engines is to improve the combustion efficiency of the jet fuel.