Coal pollution mitigation Since air is mostly nitrogen, combustion of coal often leads to production of nitrogen oxides. Sulfur dioxide and nitrogen oxides are primary causes of acid rain. For many years--before greenhouse gasses were widely understood to be a threat-- it was thought that these by-products were the only drawback to using coal. These by-products are still a problem, but they have been greatly diminished in most advanced countries due to clean air regulations. It is possible to remove most of the sulfur dioxide (SO), nitrogen oxides (NO), and particulate matter (PM) emissions from the coal-burning process. For example, various techniques are
Nitrogen dioxide This reaction is negligibly slow at low concentrations of NO characteristic of the ambient atmosphere, although it does proceed upon NO uptake to surfaces. Such surface reaction is thought to produce gaseous HNO (often written as HONO) in outdoor and indoor environments. Nitric acid decomposes slowly to nitrogen dioxide by the overall reaction: The nitrogen dioxide so formed confers the characteristic yellow color often exhibited by this acid. is used to generate anhydrous metal nitrates from the oxides: Alkyl and metal iodides give the corresponding nitrites: is introduced into the environment by natural causes, including entry from the stratosphere, bacterial