The international Network for the Detection of Atmospheric Composition Change (NDACC) has the objective to provide a consistent andstandardised set of long-term measurements of atmospheric trace gases, particles, and physical parameters via a suite of globally distributed research and observation sites. Officially operational since 1991, NDACC was established during the late 1980s in response to the need to document and understand worldwide stratospheric perturbations resulting from increased anthropogenic emissions into the atmosphere of long- lived halogenated source gases with strong ozone-depleting and global-warming potentials.

The NDACC is an international activity, it has been endorsed by the United Nations Environment Programme (UNEP) and the International Ozone Commission (IO3C) of the International Association of Meteorology and Atmospheric Sciences (IAMAS). It has also been recognised by the World Meteorological Organisation.

According to the NDACC data  protocol, measurement data becomes publicly available not later than one year after the measurement.