When an aircraft dumps fuel while in flight, what happens to the fuel?

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Dear Tom,
When an aircraft dumps fuel while in flight, what happens to the fuel?
Thomas Kuo, Chicago
Dear Thomas,
Fuel dumping is only done in emergency situations. Fuel dumping procedures designate limited areas in which it may take place and only in critical situations.
The fate of dumped jet fuel depends on the altitude at which it is released. More than 98 percent of volatile fuel jettisoned above 5,000 feet and at temperatures above freezing evaporates before it reaches the ground. What remains is widely disbursed.
If such fuel is released above 45,000 feet, it combines with atmospheric oxygen to produce carbon dioxide and water. Below that, the process is similar but takes longer. When in the presence of sunlight and nitrogen oxide, ozone can form as a byproduct. The lower the altitude of release, the greater is the effect on air quality, but there is little effect on the weather.

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