Ammonia emission characteristics and its influence on PM_2.5 in Fenhe Plain

The livestock and poultry breeding and nitrogen application in the Fenhe Plain caused a large amount of ammonia (NH₃) emissions, contributing to the increase of fine particulate matter (PM_2.5) concentration in the local atmosphere. Based on the NH₃ emission inventory of the Fenhe Plain, we analyzed the total amount of NH₃ emission and industry contribution in the region. We also designed high and low scenarios of emission reduction and applied the WRF-Chem model to study the air environmental impact of NH₃ emission in the Fenhe Plain in winter and summer of 2020, by analyzing the change of the average annual PM_2.5 concentration under different scenarios. The impact of agricultural NH₃ emission reduction on PM_2.5 pollution in the Fenhe Plain was evaluated. The results showed that: (1) The total emission of NH₃ in the Fenhe Plain was 167 000 t, concentrated in the middle and west of Yuncheng, mainly being agricultural NH₃. (2) Under the scenario of low emission reduction of ammonia in the Fenhe Plain, PM_2.5 concentration decreased by 0.7 μg/m³ in January and 0.9 μg/m³ in July; Under the high emission reduction scenario, PM_2.5 concentration decreased by 1.8 μg/m³ in January and 2 μg/m³ in July. It could be seen that ammonia emissions in the Fenhe Plain had a certain contribution to the local PM_2.5 concentration, and after taking agricultural ammonia control measures, the PM_2.5 concentration was reduced to a certain extent.