Total Chlorine Chart (image) Georgia Institute of Technology Caption This chart represents the accumulation of total organic chlorine (number per billion atmospheric molecules) in the lower atmosphere. It plots the changing contributions from human-made chlorofluorocarbons (CFCs), chlorinated solvents and the replacements for these compounds (called the HCFCs). Also shown is the almost-constant contribution from chloromethanes, which are mostly produced by natural processes. The data is derived from continuous sampling of Earth's atmosphere since 1978 at five remote locations around the world by the Advanced Global Atmospheric Gases Experiment (AGAGE), which is sponsored by NASA. Credit Chart Courtesy Derek Cunnold Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.