Combustion studies are designed to meet increasing energy requirements. They enable the development of new combustion concepts and the development of new fuels, to understand and to try to limit the formation of pollutants. Air pollution studies contribute to determine the chemical composition of the atmosphere to assess changes. They concern stratospheric ozone, greenhouse gases and aerosols, and pollutants from the lower atmosphere, with respective impacts on ultraviolet radiation at the surface, climate and air quality.