Is radiochemistry a forgotten component of atmospheric chemistry? A perspective on Edward Martell's career

In the late 1950s through the early 1960's radiochemistry emerged as a viable and potentially vital component of research in atmospheric chemistry. Edward Martell, a member of the original group of scientists to join NCAR in 1961, assumed a leadership role in this field. We examine the rise and fall of radiochemistry in atmospheric science by following the work and career of Martell. To set the stage for the historical study we trace the roots of radiochemistry from the period prior to World War II, when naturally occurring processes were the source of atmospheric radioactivity, and into the period of nuclear weaponry and fallout. Willard Libby was central to the development of atmospheric radiochemistry and he was Martell's mentor at the University of Chicago in the late 1940's through early 1950s. We briefly summarize Libby's work and Martell's adherence to and deviation from the philosophy of Libby and his associates. We pay particular attention to Martell's early work at NCAR that combined laboratory and fieldwork to study the presence of radioisotopes in the stratosphere. The early successes were followed by Martell's decision to leave mainstream atmospheric science to pursue his interest in health physics and lung cancer while remaining at NCAR. We conclude with a discussion of the promise of atmospheric radiochemistry and its decline in the mid-1970s. In this context we review problems that have been addressed as well as potentially fruitful areas that conceivably would benefit from a radiochemical research component.