Nitrogen emissions in the form of nitrogen oxides (NOX) or ammonia (NH3) contribute to the formation of groundlevel ozone and secondary fine particulates, which, together with nitrogen dioxide, are major air pollutants with significant impacts on human health. In addition, ammonia and ground-level ozone cause damage to crops and natural ecosystems. Excess reactive nitrogen lost to the environment disrupts natural cycles and results in eutrophication and acidification of ecosystems, which are among the leading causes of biodiversity loss. The release of reactive nitrogen also jeopardizes groundwater quality. Furthermore, the increased nitrogen availability in ecosystems as well as the application of fertilizers lead to emissions of nitrous oxide which is increasingly contributing to climate change.