He was assigned to work with a research group studying the earth's atmosphere. One of the scientists, a physicist named Tony Hansen , was part of this group.
Soot is a major atmospheric pollutant.
Tony developed a device to measure this pollutant, and he introduced Dean to its use. After learning more about the instrument, Dean and Tony discussed the possibility of developing a similar device that could be easily understood, built, and operated by students. They challenged themselves to make an instrument that would be inexpensive , so that teachers could afford to assemble it on their small science budgets. Tony and Dean built the instrument out of these simple materials and they tested it. Tony had developed research collaborations with scientists in Eastern Europe even before the Berlin Wall fell.