Sulphur Emission Control Area traces of heavy metals, refined petroleum products containing halogen compounds, sewage sludge and sludge oil. The Marine Environment Protection Committee (MEPC) has strongly encouraged members to use the scheme to report the greenhouse gasses emissions. Those gasses include Carbon dioxide, Methane, Nitrous oxide, Hydrofluorocarbons, Perfluocarbons, and Sulfur hexafluoride. The purpose of making the guidelines on CO2 emissions is to develop a system that would be used by ships during a trial period. In 2013 new regulations described in a chapter added to the MARPOL Annex VI came into effect in order to improve "energy efficiency of international shipping. The regulations
Acidic oxide Some non-metal oxides, such as nitrous oxide (NO) and carbon monoxide (CO), do not display any acid/base characteristics. Acidic oxides can also react with basic oxides to produce salts of oxoanions: Acidic oxides are environmentally relevant. Sulfur and nitrogen oxides are considered air pollutants as they react with atmospheric water vapour to produce acid rain. Although it is difficult to classify these oxides as acids, the property is manifest in reactions with bases. For example, carbon dioxide reacts with alkali. For this reason, alkali is kept in stoppered vessels to inhibit reaction with atmospheric carbon dioxide. In geochemistry complex silicates