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
Higher sulfur oxides forms of solid SO) with oxide bridges (−O−) replaced randomly by peroxide bridges(−O−O−). As such these compounds are non-stoichiometric. Higher sulfur oxides Higher sulfur oxides are a group of chemical compounds with the formula SO where x lies between 0 and 1. They contain peroxo (O−O) groups and the oxidation state of sulfur is +6 as in SO. Monomeric SO can be isolated at low temperatures (below 78 K) following the reaction of SO and atomic oxygen or photolysis of SO–ozone mixtures. The favoured structure is: Colourless polymeric condensates are formed in the reaction of gaseous SO or SO with