Inventory of North American Hg Emissions to the Atmosphere

Looking at emission quantities of chemicals is useful for an initial comparison of sources, but such a comparison does not relate linearly to health risk to human and non-human populations, but is a key input for risk assessment. Accurate emissions data are just now becoming available in the US for the trace element, mercury (Hg). We can use these emissions estimates to constrain risk assessments, to bound emissions for countries which lack data, and to further constrain the global cycle. Two parts of the equation remain highly uncertain: the amount of emitted Hg that participates in the global cycle and the quantification of natural sources; the latter is our greatest research need.