Nitrogen Oxides

Environmental and Health Impacts

Emissions of nitrogen oxides go nearly hand in hand with the use of fossil fuels as an energy source. These emissions also provide one of the best reasons to curb or eliminate the use of these fuels. The chemical composition of nitrogen oxides allows [Page 991]them to be easily combined with other pollutants; this can then cause the formation of separate toxic substances. For example, nitrogen oxides could combine with sulfur dioxide to create acid rain, acid fog, acid snow, or harmful dry particulates. Once created, these substances, which are made up of nitrogen oxides and sulfur dioxide, are capable of harming cars, new and historic buildings, bodies of water, and water-dependent ecosystems.

In addition to creating acid rain and similar substances, nitrogen oxides also damage bodies of water via eutrophication, a process that occurs when the atmosphere of a given region possesses an excess of nitrogen oxides. In this situation, the ecosystem attempts to balance the excess nitrogen oxides by absorbing them into available bodies of water. If severe enough, this process may impact the ecosystems contained in those water bodies by changing the chemistry of the water and, in turn, inhibiting the absorption of oxygen into that water. Finally, when water is depleted of oxygen, animal life is unable to flourish, or even survive. This problem has been particularly damaging in the Chesapeake Bay, where the absorption of nitrogen oxides created massive dead zones in the 1970s and 1980s; the bay is still suffering the ill effects of this problem to this day.

Additional harmful effects of nitrogen oxides include global warming and the stunting of plant growth. Nitrogen oxide has been shown to be a greenhouse gas. As such, the introduction of massive quantities of these chemicals into the atmosphere is causing worldwide temperatures to rise. The corresponding increases in temperatures have been proven to be causing glaciers to melt on an unprecedented scale. This melt, in turn, has caused sea levels to rise. While glaciers are not yet completely melted, rising sea levels have already caused the destruction of human settlements and numerous ecosystems. This destruction will only continue unless radical changes are made to the way human society produces energy. The leading cause of nitrogen oxide introduction into the atmosphere is automobile emissions, followed by electrical power plants.

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