What is one of the most pervasive types of pollution, yet is a rare type that completely disappears from the environment the moment we eliminate the source?
Polluted water stays polluted well past the time the contamination enters it. The same is true for air. Contaminated soil can stay that way for years on end, and various types of litter and other debris can outlive anyone reading these words today.
So what type of pollution disappears immediately after we stop adding more pollution?