Exposure to oxides of nitrogen may lead to death from any of three different types of pulmonary lesions, due to reduced partial oxygen pressure in the lungs: sudden death may result from bronchospasm and respiratory failure; otherwise, death can arise from delayed pulmonary oedema; or inflammatory changes termed bronchiolitis fibrosa obliterans, an auto-immune response. Exposure may also cause morbidity in new-born children. Damage to the environment include a brown haze in city air, acute injury to plants, and localized destruction of forests near large industrial sources.
Oxides of nitrogen (NOx) are ubiquitous pollutants emitted by internal combustion engines, power stations, furnaces, cars and fertilizers.
Once emitted into the atmosphere, nitrogen may be deposited locally or may travel great distances before deposition. Many industrial and urban centers of the central USA emit nitrogen that is not only deposited locally downwind, but also as far away as the east coast of the USA. More than 3.2 million tons of atmospheric nitrogen is deposited on the United States' watersheds each year. In addition, a sizable amount of atmospheric nitrogen is deposited in the Atlantic ocean. It is suggested that that 18% to 27% of the total NOx emitted over the eastern USA is advected over the Atlantic Ocean and deposited.