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,
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