الوصف

The characteristic of a particular gasoline blend to resist igniting too early which causes knocking and reduces efficiency in reciprocating engines is measured by its octane rating, which is produced in several grades. Tetraethyl lead and other lead compounds, once widely used to increase octane ratings, are no longer used except in aviation,[3] off-road and auto-racing applications.[4] Other chemicals are frequently added to gasoline to improve chemical stability and performance characteristics, control corrosiveness, and provide fuel system cleaning. Gasoline may contain oxygen-containing chemicals such as ethanol, MTBE, or ETBE to improve combustion. Gasoline can enter the environment combusted, both as liquid and as vapor, from leakage and handling during production, transport, and delivery e.g., from storage tanks, from spills, etc. As an example of efforts to control such leakage, many underground storage tanks are required to have extensive measures in place to detect and prevent such leaks. Gasoline contains known carcinogens. When burned, one liter of gasoline emits about 2.3 kilograms of CO2, a greenhouse gas, contributing to human-caused climate change. Oil products, including gasoline, were responsible for about *2% of CO2 emissions worldwide in ***1.