Nitrogen Pollution, Plants and Human Health

Abstract

Limited supply of reactive nitrogen compounds had been a key constraint to human development before the nineteenth century and mankind would rely heavily and entirely on fossil nitrogen and manure cycling for nitrogen needs. With the development of Haber-Bosch process mankind found a way to an almost inexhaustible supply of cheap reactive nitrogen. However humans could not foresee that the monolithic increase in the use of reactive nitrogen compounds aggravated by fossil fuel burning would culminate into a diverse array of environmental problems throughout the world. The learning to produce reactive nitrogen has come with huge costs to humans primarily due to mismanagement in its use. Agricultural practices followed worldwide generally have very low nitrogen use efficiency, which decreases further with increasing nitrogen inputs. This has led to increased losses of reactive nitrogen to the environment. These nitrogen losses have led to nitrate pollution of water courses and emissions of both ammonia and nitrous oxide to the atmosphere, with impacts on biodiversity and climate change. At the same time high-temperature combustion processes in industry and transport, which convert atmospheric di-nitrogen to nitrogen oxides, and the burning of fossil fuels has found humanity releasing reactive nitrogen directly into the atmosphere. These nitrogen compounds react with particles in the air we breathe and damage human health. Even with this brief listing of issues, it is evident that the unmortgaged human perturbation of the nitrogen cycle is having very dire consequences on the human health and environment that one could not have thought of. Therefore by assembling a handy summary on the issue of nitrogen, this chapter will serve as an essential reference for academicians, researchers and policy makers throughout the world.