Direct cause of global environmental problems such as global warming and global air pollution is the increase of atmospheric trace constituents by anthropogenic activities. Typical atmospheric trace constituents are greenhouse gases such as carbon dioxide, methane, nitrous oxide, etc., as well as air pollutants such as aerosols, ozone, nitrogen oxides, sulfur oxides, carbon monoxide, volatile organic compounds (VOC), and so forth. They cause climate change by absorbing and reflecting infrared radiation from earth surface and solar radiation, and also give environmental impacts to ecosystem and human beings. Change of atmospheric composition is called air quality change from the viewpoint of environmental impacts. Recent research revealed that climate change and air quality change are closely inter-related with feedbacks.

The Atmospheric Composition Research Program aims at elucidating the cause of temporal and spatial variability of atmospheric composition related to the climate and air quality change by combining data from satellite/ground-based observation and modeling studies, and at serving for countermeasures of global warming and global air pollution.

Carrying out these studies, in order to enhance our international presence, we join TransCom Project, international inter-comparison of global three dimensional transport models for greenhouse gases, and also participate Atmospheric Brown Cloud-Asia (ABC), a new UNEP project for studying climate and environmental impact of air pollution in Asia.