Whatever happened to acid rain?

Discover what causes acid rain, and how scientists were able to largely eliminate this major environmental threat.

In 1963, scientists studying Hubbard Brook Experimental Forest made a shocking discovery. Their most recent rainfall samples were nearly 100 times more acidic than usual; which could destroy the area’s ecosystems in a matter of decades. What was causing this deadly rainfall? And what could be done to stop it? Joseph Goffman details how scientists transformed this major threat into a minor issue.