Development Of A High-resolution Gridded Ammonia Emission Inventory In The Yangtze River Delta

Ammonia is the only gaseous alkaline substance in the atmosphere.Ammonia emission,on the one hand,will reduce the harm of acid rain,on the other hand,it is also a key factor leading to the formation of haze,soil acidification,water eutrophication and other environmental problems.With the acceleration of urbanization in the Yangtze River Delta,the characteristics of regional air compound pollution are becoming more and more obvious,which is not conducive to human health.Therefore,the formulation of ammonia emission inventory in the Yangtze River Delta region and the exploration of the characteristics and spatial and temporal distribution of ammonia emission in the region can provide a scientific basis for the formulation of relevant pollution prevention and control measures.The main conclusions of this study are summarized as follows:In 2017,the total ammonia emission from anthropogenic sources in the Yangtze River Delta region was 986.0kt,and agricultural sources accounted for a large proportion,up to80.2%.Laying hens contributed the most to ammonia emissions from livestock and poultry sources,accounting for up to 36.0%.Ammonia emission from livestock manure in the fertilization stage accounted for the largest proportion in the total livestock and poultry sources,accounting for 50.2%.Flue gas denitrification is the most important sub-source of waste treatment sources,accounting for up to 81.2%;The denitration ammonia emission of flue gas in thermal power generation industry is the largest,reaching 48.4kt.Yancheng and Xuzhou,respectively,are the two largest ammonia emitters in the Yangtze River Delta region,accounting for 9.4%and 9.0%of the total emissions in the Yangtze River Delta.The average NH₃emission intensity in the Yangtze River Delta in 2017 was 2.9 t·km^-2.Based on the uncertainty analysis of key agricultural sources,the ammonia emissions of agricultural sources in the Yangtze River Delta region in 2017 ranged from 670.0kt to1473.0kt in the 95%confidence interval.The uncertainty range of ammonia emission from nitrogen fertilizer application sources is the largest,ranging from-56.3%to 96.3%.In general,the uncertainty range of ammonia emissions from agricultural sources is-32.3%to 48.8%,which is relatively small,indicating that the emission estimated in this study is relatively reliable to a certain extent.From the sensitivity analysis,urea,broilers and laying hens had a greater impact on the output of the emission inventory,and the disturbance was greater.In terms of spatial distribution,the high value areas of agricultural sources are mainly concentrated in northern Jiangsu and northern Anhui.For non-agricultural sources,the ammonia emission in the city center is relatively large,and the high value area is mainly scattered in the southern part of Jiangsu and Shanghai.In general,the ammonia emission in the Yangtze River Delta presents an obvious trend of higher in the north and lower in the south,and the high value areas are mainly concentrated in the developed agricultural and animal husbandry areas,such as the rural areas of Xuzhou,Yancheng,Bengbu and Nantong.In terms of time distribution,from the overall trend,ammonia emissions from livestock and poultry breeding and nitrogen fertilizer application sources were small at the beginning and end of the year,which showed an upward trend after January,reached the maximum in July,and then began to decline,and returned to the minimum in December.