An ammonia emissions inventory for agricultural sources in Hefei, China

A comprehensive agricultural inventory of ammonia emissions for 2017 in Hefei was established on the basis of the specific emission factors and county-level activity data. The emissions over a 1 km × 1 km grid and the associated monthly variations were distributed on the basis of land-use type and meteorological conditions, respectively. The total ammonia emissions were 27,242.7 t in 2017 in Hefei, to which livestock was the top contributor, accounting for 54.5%. Two major contributors to livestock waste were broilers and laying hens, which contributed 34.5% and 22.2% of the total emissions, respectively. Changfeng, Feixi, and Feidong counties, with more developed agriculture than other counties, accounted for a large proportion of the total ammonia emissions—as much as 28.5%, 24.5%, and 21.0%, respectively. The average emissions density of the whole region was 2.4 t km−2, and the higher values were mostly in areas with denser populations. Seasonally, peak ammonia emissions occurred in summer.