Source and Distribution of Atmospheric Ammonia in India

The monograph describes the mixing ratios of ambient NH3 and other trace gases (NO, NO2, CO, SO2, and HNO3) and its interaction over urban and suburban areas, the Himalayan region and oceanic region of India. The average mixing ratios of ambient NH3, NO, NO2, SO2 and CO were recorded as 19.3 ± 4.4 ppb, 21.1 ± 5.8 ppb, 18.6 ± 4.6 ppb, 1.7 ± 0.5 ppb and 1.8 ± 0.8 ppm, respectively in megacity Delhi. The average mixing ratios of ambient NH3, NO, NO2 and SO2 have recorded as 7.0 ± 2.6 ppb, 3.1 ± 1.2 ppb, 3.9 ± 1.4 ppb and 1.7 ± 0.7 ppb, respectively over the Himalayan region of India. The comparatively low value of these trace gases was recorded over the Bay of Bengal. The results emphasized that the traffic could be one of the dominant sources of ambient NH3 at the urban sites of India. NH3 emission from rice-wheat cropping system of subtropical agricultural soil of Delhi, India has also been demonstrated. About 9% of the applied fertilizer N was lost as NH3 during the rice-wheat cropping system. Relationship of NH3, NOx, SO2, and HNO3 and ionic species of PM2.5 indicate the dominant role of ambient NH3 in the formation of secondary inorganic aerosols over the urban sites of India.