Study on the relationship of WSIS of PM_2.5 with NH₃ and other trace gases over Delhi, India

The water-soluble ionic species (NH₄⁺, SO₄^2-, NO₃^- and Cl^-) of PM_2.5 and trace gases (NH₃, NO, NO₂, SO₂, HNO₃) were estimated to study the relationship of ambient NH₃ in the formation of secondary inorganic aerosols in Delhi, India from January 2013 ̶ December 2018. During the study period, the average concentrations of NH₃, NO, NO₂, SO_2, and HNO₃ were 19.1±3.8 ppb, 20.8±4.3 ppb, 17.9±4.2 ppb, 2.45±0.47 ppb, 1.11±0.35 ppb, respectively. The concentrations of trace gases were higher during the post-monsoon season whereas the concentrations of ionic components in PM_2.5 were estimated higher in winter. The correlation matrix of trace gases reveals that the ambient NH₃ neutralizes the acid gases (NO, NO_2, and SO₂) at the study site. The study reveals that the abundance of particulate NH₄⁺ at the study site neutralized the SO₄^2-, NO₃^-, and Cl^- particles during all the seasons.