Nitrogen Oxide (NOx)

In the maritime context, Nitrogen Oxide (NOx) refers to a group of highly reactive gases that contain nitrogen and oxygen in varying amounts. Many of the nitrogen oxides are colorless and odorless. However, one common pollutant, nitrogen dioxide (NO2) along with particles in the air can often be seen as a reddish-brown layer over many urban areas. NOx gases are formed when the fuel being used in ships' engines is burned at high temperatures. The primary sources of NOx are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fuels. In the maritime industry, NOx emissions are a significant concern due to their contribution to air pollution, which can have harmful effects on both the environment and human health. They contribute to the formation of smog and acid rain, as well as the depletion of the ozone layer. To mitigate the impact of NOx emissions, the International Maritime Organization (IMO) has set limits on the amount of NOx that can be emitted from ship exhausts, which is enforced through the MARPOL Annex VI regulation.