The Existence of Mercury Nanoparticles

In this work, we show that previously unknown mercury-containing nanoparticles exist in the air using high-resolution scanning transmission  electron microscopy imaging (HR-STEM). Deploying an urban-air feld campaign near a mercury point  source, we provide further evidence for mercury nanoparticles and determine the extent to which  these particles contain two long suspected forms of oxidized mercury (mercuric bromide and mercuric  chloride) using mercury mass spectrometry (Hg-MS). Using optical particle sizers, we also conclude  that the conventional method of measuring gaseous oxidized mercury worldwide can trap up to 95%  of nanoparticulate mercuric halides leading to erroneous measurements. Finally, we estimate airborne  mercury aerosols may contribute to half of the oxidized mercury measured in wintertime Montréal  urban air using Hg-MS. These emerging mercury-containing nanoparticle contaminants will infuence  mercury deposition, speciation and other atmospheric and aquatic biogeochemical mercury processes  including the bioavailability of oxidized mercury to biota and its transformation to neurotoxic organic  mercury.