Measurement of ambient NH 3 over Bay of Bengal during W_ICARB Campaign
Concentrations of ambient NH 3, NO, NO 2 and SO 2 were measured over Bay of Bengal (BoB) during 28 December 2008 to 25 January 2009 to study their diurnal variation and relationship of NH 3 with other trace gases over BoB. The measurements were done under the winter phase of Integrated Campaign on Aerosols and Radiation Budget (W_ICARB). For the first time, ambient NH 3 was monitored precisely over BoB based on chemiluminescence method, having estimation efficiency more precise than the chemical trap method. The average concentration of ambient NH 3, NO, NO 2 and SO 2 were recorded as 4.78 ± 1.68, 1.89 ± 1.26, 0.31 ± 0.14 and 0.80 ± 0.30 μg m −3, respectively, over BoB. The prominent latitudinal and longitudinal variations of the trace gases were observed over BoB, whereas NH 3 and NO showed the non-significant diurnal variation. Results reveal that the concentration of ambient NH 3 negatively correlated with ambient NO 2 ( r2 = −0.56), SO 2 ( r2 = −0.58) and ambient temperature ( r2 = −0.27) during the study.