In China, nitrogen leaves pollution haze

Futurity: China, the amount of nitrogen from industry, cars, and fertilizer that fell on land and in water increased by 60 percent each year from 1980 to 2010, a new study reports. It’s no secret that China is faced with some of the world’s worst pollution. Until now, however, information on the magnitude, scope, and impacts of human-caused nitrogen emissions was lacking.

Xuejun Liu and Fusuo Zhang at China Agricultural University in Beijing led the study, which is part of an ongoing collaboration aimed at reducing agricultural nutrient pollution while increasing food production in China—a collaboration that includes Peter Vitousek, a biologist at Stanford University and Pamela Matson, a Woods Institute senior fellow and dean of the School of Earth Sciences.

For the study, researchers analyzed all available data on bulk nitrogen deposition from monitoring sites throughout China during the past 30 years. In that time, the country has become by far the largest creator and emitter of nitrogen globally.

Its use of nitrogen as a fertilizer increased about threefold from the 1980s to 2000s, while livestock numbers and coal combustion increased about fourfold, and the number of automobiles about twentyfold (all of these activities release reactive nitrogen into the environment).

Increased levels of nitrogen have led to a range of deleterious impacts, including decreased air quality, acidification of soil and water, increased greenhouse gas concentrations, and reduced biological diversity...

NASA image of haze over eastern China, from NASA