b1g-fragment02 890
Trace gases in the atmosphere are key components of the cycles of such elements as carbon , nitrogen , oxygen , sulphur and the halogens ; as is now well known , their concentrations are much influenced by biogenic and anthropogenic activities and the concentrations of such gases as carbon dioxide , ozone , methane , nitrous oxide and the chlorofluoromethanes ( CFMs ) strongly affect radiative transfer and provide a link with the physical climate system .