It is possible to estimate emissions using inverse modeling techniques from accurate mixing ratios of many anthropogenic trace gases (e.g., nitrous oxide, chlorofluorocarbons, halons, hydrochlorofluorocarbons, hydrofluorocarbons, sulfur hexafluvoide, and perfluorocarbons) measured worldwide. Comparing existing programs with other network monitoring programs can help enrich the data base for modeling the atmosphere. Model studies are important to determine whether international agreements to reduce the emissions of greenhouse gases or ozone-depleting chemicals (e.g., Montreal Protocol) are carried out. From these models, we can also determine many important atmospheric parameters. For example, OH is Nature’s cleanser, and it can remove many pollutants from the atmosphere. For some trace gases (e.g., CH3CCl3, HCFC-14lb, and C2Cl4) that have accurate industrial emission estimates and are destroyed by OH, it is possible to determine the global distribution of OH. NOAA Global Monitoring Laboratory scientists measure trace gas species produced by anthropogenic and natural processes at their worldwide sites. Some compounds (e.g., CH3CCl3 and CH3Br) have significant sinks in the ocean. Our goal is to determine the strengths of the sources and sinks of important trace gases in order to help policy makers plan strategies for reducing global emissions of harmful pollutants.