There has been a huge positive turnaround in America's environmental quality over the past 40 years.

The Clean Air Act's "most-wanted" pollutants have fallen by two-thirds since 1970.

Airborne lead is down nearly 99 percent since 1970, which has contributed to a more than 80 percent decline in blood lead levels in children, increasing their IQ.

The use of toxic chemicals has declined by a whopping 45 percent since 1988.

The Great Lakes, on the brink of becoming the American Dead Sea in 1970, are today thriving.

The chief factors in improving environmental conditions have been economic growth and technological improvement.