woensdag 23 april 2014

How One Man Changed Our Atmosphere

A reflection on the atmospheric legacy of Thomas Midley

Before photosynthesis evolved, our atmosphere was oxygen-free. When photosynthetic microorganisms started producing oxygen as a  waste product, it was first removed from the atmosphere by reduced minerals, mostly iron. This led to the deposition of banded iron formations. Later, the Great Oxygenation Event (about 2.3 billion years ago) added oxygen to the Earth's atmosphere. This series of events shows how a group of organisms dramatically changed the composition of the atmosphere. Quite impressive, right? Not if you compare it to the work of an American chemist...

Banded Iron Formation
Thomas Midley Jr. was born in Beaver Falls, Pennsylvania on the 18th of May 1889. He produced two products that have greatly altered the atmosphere. In 1923, he discovered that the addition of Tetraethyllead (TEL) prevents the "knocking" of internal combustion engines. The addition of TEL to gasoline has led to the release of large quantities of lead into the atmosphere with detrimental effects on human health. He also developed the first chlorofluorocarbons (CFCs). Three decades after his death, it became clear that CFCs deplete atmospheric ozone, leading to the well-known hole in the ozone-layer. All in all, this one man is (indirectly) responsible for increased lead concentrations in the atmosphere and the hole in the ozone-layer. Now that is impressive!

Thomas Midley Jr.
In addition, his death in 1944 is equally dramatic. Having contracted polio, he devised a system of strings and pulleys to help others lift him from the bed. Unfortunately, he became entangled in the ropes and died of strangulation.

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