NITROUS-OXIDE IN THE EARTHS ATMOSPHERE

Nitrous oxide (N2O) is an important atmospheric trace gas. Changes in the concentration of N2O in the atmosphere have evoked considerable interest because of its role in (i) regulating stratospheric ozone levels, and (ii) contributing to the atmospheric greenhouse phenomenon. The global concentration of N2O in the atmosphere has been rising since the start of the Industrial Revolution, before which the concentration was almost constant at about 280-290 ppbv. In AD 1990, it reached about 310 ppbv and is rising at a rate of 0.5-1.1 ppbv (i.e. 0.2-0.3%) per year. In this paper, the history of N2O in the Earth's atmosphere, together with its latitudinal and altitudinal distributions, and seasonal oscillations, are described.