Mercury Concentration in the Atmosphere in Chicago A New Ultrasensitive Method Employing Amalgamation

Abstract

During the past two years, the Chicago Department of Environmental Control chemistry laboratory has developed a prototype sensor for measuring low levels of mercury found in the free or ambient atmosphere. Earlier studies of mercury in the Chicago area postulated that most of the mercury in the atmosphere should condense onto particulates and be collectable on filters. The results of the work presented here show that this may not occur. Analysis of composites of Chicago high volume particulate filters results in an average of 4 nanograms/m3 (range 2-10 nanograms/m3). This compared with a typical average of elemental mercury measurements of 22 nanograms/m3 (range 5-60 nanograms/m3). Thus, it is obvious that particulate borne mercury, at least as analyzed from a high volume filter paper, is not as significant as the total or elemental mercury existing in the metropolitan area. A direct method for collecting mercury and measuring in a flameless atomic absorption unit yields very good results.