Temporal variability of atmospheric Total Gaseous Mercury and its correlation with meteorological parameters at a high-altitude station of the South India

Diurnal and seasonal variation of atmospheric Total Gaseous Mercury (TGM) were studied for the first time in a high altitude station, Kodaikanal, India. To achieve this, an automated continuous mercury vapour analyzer was used in the study area between November, 2012 and September, 2013. In this pilot study the annual mean atmospheric TGM concentration was found to be 1.53 ng/m3, with a range from 0.83 to 3.25 ng/m3 and with a lognormal frequency distribution pattern. The mean seasonal concentration of TGM was found to be in the following order: summer > winter > northeast monsoon > southwest monsoon. Significant temporal differences in the TGM concentrations indicated strong environmental control regulated by seasonal changes in this high altitude rural area. The study further revealed that the day time TGM concentration was strongly modified by solar radiation, evaporation and rainfall. Moreover, this is the first study in the Indian subcontinent with continuous monitoring of the temporal changes of TGM and its relation to other micrometeorological factors.