ABSTRACT
This chapter will review some of the networks attempting to provide data at global, regional and local scales. The data from these networks, however, will never answer all the questions people have about changes in the composition of the atmosphere. In 1989, the World Meteorological Organization (WMO) set up Global Atmosphere Watch (GAW). This brought together a number of longer running programmes including the Global Ozone Observing System (GO3OS) which started in the 1950s and the Background Air Pollution Monitoring Network (BAPMoN) which started in the 1960s. GAW is basically a voluntary programme where the core funding comes from the members of the WMO and other participating countries. It links in to broader projects such as the Global Climate Observing System (GCOS). The GAW system comprises both global and regional networks. Global stations are located in areas remote from regional pollution sources and unlikely to be affected by natural pollution events such as volcanic eruptions or dust storms.
