The complexity of the physical and chemical processes that control the composition of the atmosphere on different scales is depicted on figure below. To address such a complex system, GAW research activities are directed towards conducting observations to document changes in atmospheric composition, continuous improvement of the observational and data management infrastructure, analyses of the data to improve knowledge on the processes controlling atmospheric composition change, and the development of GAW products and services.
These research activities are supported through the infrastructure reflected in figure below, which includes observing systems supplemented by a set of Central Facilities supporting the quality assurance system, a data management system, advisory groups, expert teams and a steering committee. General governance of the programme is organized through focal areas. Various GAW expert groups exist under the oversight of the WMO Commission for Atmospheric Sciences (CAS) and its Environmental Pollution and Atmospheric Chemistry Scientific Steering Committee (EPAC SSC). EPAC SSC takes the responsibility for the programme strategic leadership and coordinates cross-cutting thematic activities and overarching activities in GAW.