fuel is only dumped in extreme emergencies. When it is dumped most of it will dissolve in the atmosphere and what is left will fall to the ground

most of it dissipates before it reaches the earth.

First of all, airplanes dumping fuel is a rare situation that only happens in the most dire emergencies. The only reason fuel is ever dumped is to avoid an overweight landing. Aircraft may be able to take off at a particular weight but cannot land with the same weight. These extra pounds come from the jet fuel. If the flight goes normally, enough fuel is burned off that the plane will now be at it's safe landing weight when it reaches the destination airport. When a problem occurs during takeoff or climbout, the plane may turn around and land again at the same airport or a nearby alternate. Since the plane is too heavy to land, the pilots will jettison fuel from pipes and valves normally located on the wings. If fuel is being dumped, it's usually at an altitude above flight level 030. (3000 ft) At this altitude the fuel evaporates before touching the ground. However, since this is only done in emergencies, the plane may not have enough time to climb to a higher altitude. In this case, the fuel may be dumped at a lower altitude, and yes, it will rain down and can pollute areas with terrible smells. Pilots may also elect for an emergency overweight landing instead of a fuel jettison if the situation is urgent. Sometimes pilots may also try to troubleshoot a problem in the air while circling the airport. This burns off fuel and gives pilots extra time to evaluate the situation. So leave with this note, fuel is only dumped in emergencies, if dumped at an altitude above a few thousand feet, it will evaporate. If it is dumped any lower, it will touch the ground and can cause problems with fumes. Look at it this way, I would rather my backyard smell like kerosene for a few days if it prevented a more serious consequence.