“Atmospheric brown clouds (ABCs), observed as widespread layers of brownish haze, are regional scale plumes of air pollutants, consisting of mainly aerosol particles (such as black carbon (BC) and non BC), and precursor gases (e.g. CH4, CO,NMVOCs, NOx), which produce aerosols and ozone in the atmosphere. ABCs and their interaction with build-up of greenhouse gases (GHGs) significantly affect the regional climate, hydrological cycle, glacial melting, agriculture production, and human health.
The United Nations Environment Programme (UNEP) commissioned the Atmospheric Brown Cloud (ABC) Programme in 2002, with a team of renowned scientists, to further continue the studies to understand the impacts of ABCs on climate and health and equip the policy makers with science-based information in order to underpin the actions on mitigation of ABCs at regional and global levels.
The ABC Programme implemented through three sub-programmes, namely, Observatory and Capacity Building Programme, Impact Assessment Programme, and Mitigation and Awareness Programme.