Uncovering the Gaps in Bulk Atmospheric Mercury Speciation

English Abstract:

A global concern because of its potential for long range transport and toxicity, atmospheric mercury is loosely defined as gaseous elemental mercury (GEM), reactive gaseous Hg²⁺ mercury species (RGM) and particulate mercury (Hg_p) with the chemical speciation of RGM long recognized as unknown. Elemental and inorganic mercury are typically measured in air by cold vapour atomic fluorescence spectroscopy (CVAFS), with inorganic mercury collected on a KCl denuder for decomposition to elemental mercury for CVAFS analysis (KCld-CVAFS). KCld-CVAFS provides bulk mercury speciation information but cannot distinguish between forms of inorganic mercury collected. Mercury fluxes from inorganic mercury sources were calibrated using the KCld-CVAFS to ensure a consistent, quantifiable supply of gaseous inorganic mercury. Using a variety of techniques such as mass spectrometry, condensation particle counters, electron microscopy and nanoparticle tracking analysis, the speciation and phase of common proxies for RGM will be explored and discussed.