Current and Future Emissions of Ammonia in China

Ammonia emission inventory for 1990 and 1995 as well as scenarios up to 2030 are presented for China. Emissions are estimated on a provincial level using a Regional Air pollution INformation and Simulation (RAINS) model that was developed at IIASA. Total emissions in China are estimated at 9.7 and 11.7 million tons NH3 in 1990 and 1995 and are forecasted to increase to nearly 20 million tons NH3 by 2030 in the presented scenario. The major contribution comes from N-fertilizer application and livestock, representing in the 90’s about 52 and 41 percent of total emissions, respectively. The share of fertilizer application in total emissions is expected to increase to about 61 percent in 2030, while that of livestock declines to 33 percent. Owing to a large share of ammonium bicarbonate and urea in applied N-fertilizers, the emission structure is in sharp contrast with the situation in Europe where livestock is the dominant source of ammonia and losses from N-fertilizer application represent typically about 15 to 20 percent of total. Spatial distribution of emissions is also presented at a 1x1 degree grid resolution. In 1995 the highest ammonia emission density which exceeds 100 thousand tons NH3 per grid, is observed in Jiangsu and Henan provinces. This corresponds well with the large population of pigs in these regions as well as high cattle density in Henan province. INTRODUCTION Atmospheric ammonia (NH3), sulfur dioxide (SO2) and nitrogen oxides (NOx) are among the main pollutants leading to acidifying deposition. Since typically, emissions of the latter two are larger and often associated with big stacks and transport sources that are easy to blame for the pollution, NH3 has received a lot less attention in the past. This has been the case in Europe, North America and also Asia where rapidly growing emissions of SO2 grabbed the headlines. China is no exception, fast economic growth means increased energy demand that is satisfied by primarily fossil fuels that in consequence might lead to high SO2 and NOx emissions and increased acid deposition in China and elsewhere. The issue of acidification in China has been studied in the last years and several papers reviewed the present and future emissions of SO2 and NOx . Only few studies on ammonia emissions in China are available. Although there are several global or regional assessments that include China or East Asia, they often lack the necessary level of detail for a regional assessment. Importance of NH3 is growing, partly due to continued efforts to reduce emissions of the other acidifying pollutants but also because of its role in eutrophication of ecosystems. Also, similarly to growing energy demand, the output of the agricultural sector is expected to grow in the coming decades as well as emissions of NH3 associated with it. Recently, several atmospheric modeling studies focusing on acidification have been initiated in East Asia. In order to analyze the present and future acid deposition in that region, spatially disaggregated emission inventories of SO2, NOx, and NH3 need to be compiled. They serve as an input to the atmospheric long-range transport models. This paper focuses on China and provides estimates of NH3 emissions in 1990 and 1995 as well as projections up to 2030. Emissions are estimated for several sectors on a provincial level using a Regional Air pollution INformation and Simulation (RAINS) model that was developed at IIASA. Spatial distribution of emissions is also presented at a 1x1 degree grid resolution.