Greenland Ice Sheet Samples Show That US Clean Air Act Had 'Dramatic Impact' On Air Pollution Emissions

Greenland's ice sheet is like a time capsule that chronicles the recent history of Earth's atmosphere, including the role humans have played in changing it. Scientists who analyzed core samples from the ice found they contained a record of chemical shifts in the air, including how efforts by the U.S. government to rein in air pollution helped improve the environment.