In the mid-1940s, A. J. Haagen-Smit led investigations into the origins of smog. Through his research he discovered that smog is created by the oxidation of organic material in the air. Haagen-Smit spent a major part of his life challenging industry in an attempt to curtail air pollution caused by burning fuels. As a result of his constant battle, factories now use smoke stacks that filter carbon fumes, and the auto industry has incorporated components to reduce pollution-causing vapors from car and truck exhaust.

Arie J. Haagen-Smit was born in Utrecht, The Netherlands, on December 22, 1900, the son of Jan Willem Adrianus Haagen-Smit and Maria Geertruida van Maanen. His father was a chemist who maintained a large science library in the home. Haagen-Smit credited his interest in science and technology to the early enthusiasm of his father's discussions about his work, and the accessibility of his family's library...