Nitrogen Oxides

Nitrogen oxides are a group of chemical compounds involving the elements of nitrogen and oxygen in different configurations. They include nitric oxide (NO), which usually takes a gaseous state and is the most stable of the oxides. Nitric oxide and other oxides are created when vehicle fuel is burned at high temperatures and they are significant pollutants. The oxides can be highly mobile and may be responsible for creating smog and ozone.

The other nitrogen oxides that can be formed include nitrogen dioxide (NO2), nitrous oxide (dinitrogen monoxide N2O), and the unstable compounds dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), and dinitrogen pentoxide (N2O5). The amalgamation of oxides created by the internal combustion process is referred to in entirety as NOx. The oxides are not all dangerous or useless: nitrous oxide, for example, is better known as laughing gas and has important medicinal uses, even if it is poisonous in uncontrolled quantities.

Various types of technology have been employed to try to reduce the creation of nitrogen oxides. One of the most successful and influential of these has been the catalytic converter, which is now compulsory to have fitted onto most forms of automobile at manufacture. However, this is inappropriate for the alternative sources of NOx production, which include factory and industrial plants burning coal or natural gas. The rapid industrialization of China is of particular relevance in this case because large numbers of Chinese factories rely upon Chinese-sourced coal for power. The nitrogen oxides produced contribute to such phenomena as acid rain, the production of toxic chemicals, and global warming. The compounds can hurt living creatures directly by leading to respiratory problems and illnesses, such as asthma. Climatic conditions and industrialization patterns mean that certain urban areas are particularly potent threats to health. Some claims have been made for clean coal consumption, which offers much lower NOx production.

The Kyoto Treaty and other international agreements address the worldwide production of nitrogen oxides as a pollutant. Most developed countries have state-level regulatory agencies to monitor the level of atmospheric pollutants and take actions of some sort against heavy polluters. In the United States, the Environmental Protection Agency is the body responsible for this task.