NH3 and NH4+ Relationship & Influence of Source and Meteorology During Different Growing Seasons at a Rural Site in Haryana(India)

Abstract:

Among the emissions of different reactive nitrogen (Nr) species, ambient ammonia (NH₃) emissions from agriculture are very important. In addition, NH₃ is an alkaline constituent of the atmosphere which plays a vital role in regulating the atmospheric acidity after interacting with the atmospheric acids viz. H₂SO₄, HNO₃, HCl to form NH₄⁺ aerosols which are generally present in the fine fraction. This study relates the variation of NH₃ and NH₄⁺ based on the influence of sources and meteorology in an agricultural dominated rural area. Average ambient concentration of NH₃ during Kharif crop season (July to October) was measured as 128.80 while that of NH₄⁺ as 1.18 µg/m³. The average concentration of NH₃ during Rabi crop season (November to April) was measured as 45.54 while that of NH₄⁺ as 5.01µg/m³. Both NH₃ and NH₄⁺ showed a significant diurnal variation indicating an influence of meteorological factors. Wind rose plots suggested that the nearby agricultural fields are the major sources for NH₃ in the ambient air at the sampling site.

Keywords: Agriculture; Ammonia; Ammonium; Atmospheric acidity; Meteorology