The Chemistry

Nitrogen compounds play a central role in atmospheric chemistry and are associated with several of today's major environmental issues.

Nitrogen oxide emissions from combustion sources are involved in the complex atmospheric processes leading to the formation of photochemical oxidants.

Such pollutants at ground level are responsible for photochemical smogs, and at higher altitudes in the free troposphere contribute to "greenhouse" warming.

Nitrogen oxides, ammonia, mainly from agricultural emissions, and their atmospheric reaction products, account for the major fraction of nitrogen deposition to terrestrial ecosystems.

Excess nitrogen deposition may have adverse environmental consequences arising from acidification or eutrophication.

This book presents the proceedings of a symposium, organized by the Royal Society of Chemistry Environment Group in February 1992, with the aim of summarizing the current knowledge and uncertainties in the atmospheric sciences, linking emissions to the key environmental effects.

Reviews of photochemical oxidants in the emission "plumes" of large combustion sources, and in urban and rural areas are presented. The critical loads concept, a method of quantifying ecosystem sensitivity, is also reviewed, together with particulate chemistry and wet deposition, key steps in the deposition process, and their synthesis in a large-scale nitrogen deposition model.

Whilst significant advances have been made in defining and understanding the physico-chemical processes governing the atmospheric behaviour of nitrogen species and their ecological effects, much research is still needed to quantify these adequately enough to permit a meaningful estimation of the results of proposed emission control strategies at the required spatial and temporal resolution.