Environmental impact of shipping engines can be higher on a port-specific basis. Ultra-low sulfur diesel (ULSD) is a standard for defining diesel fuel with substantially lowered sulfur contents. As of 2006, almost all of the petroleum-based diesel fuel available in Europe and North America is of a ULSD type. In 2016 the IMO has made new sulfur regulations which must be implemented by larger ships by 2020. Of total global air emissions, shipping accounts for 18 to 30 percent of the nitrogen oxide and 9 percent of the sulphur oxides. Sulfur in the air creates acid rain which damages crops and buildings. When inhaled,
Sulfur dioxide Sulfur dioxide Sulfur dioxide (also sulphur dioxide in British English) is the chemical compound with the formula . It is a toxic gas with a burnt match smell. It is released naturally by volcanic activity and is produced as a by-product of the burning of fossil fuels contaminated with sulfur compounds and copper extraction. SO is a bent molecule with "C" symmetry point group. A valence bond theory approach considering just "s" and "p" orbitals would describe the bonding in terms of resonance between two resonance structures. The sulfur–oxygen bond has a bond order of 1.5. There is support for