The Antarctic Troposphere Chemistry Investigation (ANTCI) is a collaborative research project funded by the Office of Polar Programs, National Science Foundation. The study involves scientists from the Carlsbad Environmental Monitoring & Research Center, NMSU; the Georgia Institute of Technology; University of Colorado Boulder, University of Arizona; University of New Hampshire; University of California Irvine; and National Center for Atmospheric Research. The studies are designed to better understand the processes controlling the tropospheric levels of reactive hydrogen radicals, reactive nitrogen, sulfur compounds, and other trace species, with the related purpose of improving the ability to interpret climate signals recorded in Antarctic ice cores. Through collaboration with a team of scientists from NOAA, the participants are making measurements of various chemicals at the South Pole where they also are collecting meteorological data and other information. Additional measurements are being made from research aircraft. The results of the studies will lead to a more comprehensive understanding of Antarctic atmospheric chemistry, as well as the factors that influence the concentrations and distributions of climate proxies in the ice cores.