Agricultural Ammonia Emission Inventory and Its Spatial Distribution in Sichuan Province from 2005 to 2014

: Based on the urban activity data and emission factors, agricultural ammonia emission inventory was developed for Sichuan province from year 2005 to 2014. Meanwhile, its historical trends, spatial distribution and the relationship between agricultural ammonia emission and PM10 concentration were analyzed. The results showed that the highest emission was estimated to be 111.9×104 t in 2006, which was reduced to 95.5×104 t in 2014. The interannual variation characteristics were different for 21 cities in Sichuan, the annual emission of Chengdu, Meishan, Zigong, Luzhou, Yibin, Panzhihua, Aba and Ganzi changed largely in the study period. Livestock source and nitrogen fertilizers were the major contributors, accounting for 72%-79% and 20%-27% of the total agricultural NH3 emission respectively. Hog, poultry and cow were the major contributors under the category of livestock sources for the most cities. It's worth mentioning that rabbit was the largest contributor in Zigong, accounting for 39% of the total livestock NH3 emission. The urban and sub-urban areas of Chengdu, the northeastern and southern part of Sichuan were the hot-spots for agricultural NH3 emission. In term of spatial distribution, there were higher emissions in the east of Sichuan and other suburban and rural areas. There was a good agreement between agricultural NH3 emission and PM10 concentration, indicating agricultural NH3 emission played an important role in the particle formation.