Steven Chillrud is a Senior Doherty Research Scientist at Lamont-Doherty Earth Observatory and co-Director of the Exposure Assessment Facility Core of Columbia University's Center for Environmental Health in Northern Manhattan. He describes himself as an environmental geochemist interested in public health research. Much of his research is focused on the role of particles in the transport, behavior and fate of chemical contaminants. These particles can be fine-grained sediments in surface water bodies such as the Hudson River, sandy particles in groundwater aquifers, or airborne particles in indoor and outdoor settings. His air pollution work includes understanding the sources, behavior and exposure pathways of airborne contaminants as well as designing and testing new air monitoring devices, either to be used at fixed indoor and outdoor locations or to be worn by people. Much of his work is done in collaboration with public health investigators to work on both local and international health issues.