Agricultural ammonia emissions inventory and spatial distribution in the North China Plain

An agricultural ammonia (NH3) emission inventory in the North China Plain (NCP) on a prefecture level for the year 2004, and a 5 × 5 km resolution spatial distribution map, have been calculated for the first time. The census database from China’s statistics datasets, and emission factors re-calculated by the RAINS model supported total emissions of 3071 kt NH3-N yr-1 for the NCP, accounting for 27% of the total emissions in China. NH3 emission from mineral fertilizer application contributed 1620 kt NH3-N yr-1, 54% of the total emission, while livestock emissions accounted for the remaining 46% of the total emissions, including 7%, 27%, 7% and 5% from cattle, pigs, sheep and goats, and poultry, respectively. A high-resolution spatial NH3 emissions map was developed based on 1 × 1 km land use database and aggregated to a 5 × 5 km grid resolution. The highest emission density value was up to 198 kg N ha-1 yr-1.