BOB HIRSHON (host):
The Clean Air Act’s frozen signature. I’m Bob Hirshon and this is Science Update.
Ice samples indicate that the U.S. Clean Air Act has successfully curtailed acid rain – a threat to plants and animals, water and soil quality, and even buildings. This according to University of Washington atmospheric scientists Becky Alexander and Lei Geng. Alexander explains that pollutants in Greenland’s ice cores mainly come from North America. Geng’s new data show that key chemical indicators of acid began rising around 1850, and peaked around 1970. That’s when Congress passed the Clean Air Act, limiting emissions that cause acid rain.
BECKY ALEXANDER (University of Washington):
And then it decreased even more, at a faster rate, around 1990, when the 1990 amendments to the US Clean Air Act were implemented.
Those amendments limited emissions even further. The ice cores provide more evidence that policy changes can have a significant environmental impact. I’m Bob Hirshon for AAAS, the Science Society.