Selin received her Bachelor of Arts in Environmental Science and Public Policy and her Master of Arts in Earth and Planetary Sciences at Harvard University in 2000. Following graduation, Selin became a Fulbright Fellow, working as a visiting researcher in Copenhagen at the European Environment Agency. There, she studied ways to improve scientific assessments of chemicals and their environmental impacts.
Following her Fulbright Fellowship, Selin returned to Harvard to receive her PhD in Earth and Planetary Sciences in 2007. There, she worked in the Atmospheric Chemistry Modeling Group with Daniel J. Jacob to understand how mercury cycles through the atmosphere, across land, and in water using a global 3-D chemical transport model. Her research extended to the politics and policy underlying mercury pollution, authoring articles in law and governance publications. Her graduate work was supported by a National Science Foundation Graduate Research Fellowship award, as well as a United States Environmental Protection Agency Science to Achieve Results Graduate Research Fellowship.
In 2007, Selin became a postdoctoral fellow at the Massachusetts Institute of Technology in the Center for Global Change Science and Joint Program on the Science and Policy of Global Change. Her research centered on atmospheric pollution and human health impacts, as well as continuing to focus on global efforts to regulate hazardous chemicals.