At Northwestern Geiger has developed a new soil science laboratory for general chemistry courses and has written two environmental chemistry modules for soil and atmospheric chemistry.
His research focuses on the special roles that surfaces and interfaces play in tropospheric and soil chemistry and their implications for climate changes and environmental pollution. His research involves using laser spectroscopy and mass spectrometry. In one example, his research group uses lasers to determine how tightly pollutants stick to environmental interfaces.
Results of Geiger's studies include the finding that the heavy-metal pollutant hexavalent chromium may linger in the ground longer than expected. This finding broadens the understanding of geochemical processes and may lead to revisions of environmental cleanup strategies. The study was highlighted in the April 2005 issue of “Chemical & Engineering News” and in “Science.”
Recently Geiger's group expanded this work to veterinary antibiotics, which are used on a massive scale in the cattle, poultry and swine industries, but whose environmental fate, including their role in the emerging threat of antibiotic resistance, is currently unknown.
Geiger's group also studies how indoor air pollutants interact with catalysts, with the goal to develop remediation strategies for indoor air pollution.
Geiger's research is supported by the Department of Energy, the National Science Foundation and the Dreyfus Foundation, among others.
Recipient of a National Science Foundation CAREER Award from 2004 to 2009, Geiger was appointed to the Editorial Board of Geochemical Transactions in 2005. He received the Distinguished Teaching Award from the Northwestern Undergraduate Chemistry Council in 2005 and the Camille and Henry Dreyfus Foundation Postdoctoral Research Fellowship Award in Environmental Chemistry in 2004.
Geiger was named a Searle Teaching Scholar in 2004 and received a Harold N. Glassman Award in 2001. He was awarded fellowships from both the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration.
He has published 20 manuscripts at Northwestern and has been an invited speaker at more than 150 meetings, conferences and universities. He is a member of the American Association for the Advancement of Science, the American Chemical Society and the American Geophysical Union.