An Analytical Method development for the Study of Chemical Species of Mercury in the Atmosphere

Abstract

Introduction: both natural and anthropogenic activities add mercury (Hg) to the atmosphere. The speciation and chemical transformation of mercury in the atmosphere can significantly influence how it is deposited on the earth’s surface. Methods: To better understand the impact of urban emissions on global mercury cycling, we developed an inexpensive technique for the reliable measurement of gaseous oxidized mercury (GOM) in air. This simple technique is based on a thermal decomposition-difference method previously developed by others for aircraft studies of gom in the remote troposphere. measurements of total atmospheric mercury (TAM) were made by decomposing all forms of mercury in ambient air to gaseous elemental mercury (GEM) at 500°c prior to detection using cold vapour atomic fluorescence spectroscopy (CVAFS). The amount of gom was determined through the difference between TAM and GEM values. results and discussion: a diurnal pattern was found for GEM, with the highest concentrations of Hg species found ranging from 2:00 to 5:00 pm and the lowest and most stable values from 9:00 pm to 6:00 am. The amount of GOM was estimated on the 5th floor balcony of pavillon prépresident-Kennedy at université de Québec à montréal to be 14.7 ± 10.3 ng∙m-3 (arithmetic mean from eight groups of Tam-gem differences in the afternoons of july 12 and 14, 2011 and 95% confidence interval). The inconsistent GOM result, in addition to a large error value, suggests the need for further investigation, and to compare the efficiency of this method to previously established methods to identify and quantify the mercury species in urban gom.