The Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT), developed by NOAA’s Air Resources Laboratory, is one of the most widely used models for atmospheric trajectory and dispersion calculations. We present the model’s historical evolution over the last 30 years from simple hand-drawn back trajectories to very sophisticated computations of transport, mixing, chemical transformation, and deposition of pollutants and hazardous materials. We highlight recent applications of the HYSPLIT modeling system, including the simulation of atmospheric tracer release experiments, radionuclides, smoke originated from wild fires, volcanic ash, mercury, and wind-blown dust.

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NOAA’s HYSPLIT Atmospheric Transport and Dispersion Modeling System

The Lancet Commission on pollution and health

The science of the total environment

 Many atmospheric chemicals occur in the gas phase as well as in liquid cloud droplets and aerosol particles Therefore, it is necessary to understand the distribution between the phases According to Henry's law, the equilibrium ratio between the abundances in the gas phase and in the aqueous phase is constant for a dilute solution Henry's law constants of trace gases of potential importance in environmental chemistry have been collected and converted into a uniform format The compilation contains 17 350 values of Henry's law constants for 4632 species, collected from 689 references It is also available at http://wwwhenrys-laworg 

/pdf/compilation-of-henry-s-law-constants-version-4-0-for-water-58il9q0ogv.pdf

Compilation of Henry's law constants (version 4.0) for water as solvent

Biogeochemistry of the Human Environment.- The Biosphere.- Soils.- Waters.- Air.- Plants.- Humans.- Biogeochemistry of Trace Elements.- Trace Elements of Group 1 (Previously Group Ia).- Trace Elements of Group 2 (Previously Group IIa).- Trace Elements of Group 3 (Previously Group IIIb).- Trace Elements of Group 4 (Previously Group IVb).- Trace Elements of Group 5 (Previously Group Vb).- Trace Elements of Group 6 (Previously Group VIb).- Trace Elements of Group 7 (Previously Group VIIb).- Trace Elements of Group 8 (Previously Part of Group VIII).- Trace Elements of Group 9 (Previously Part of Group VIII).- Trace Elements of Group 10 (Previously Part of Group VIII).- Trace Elements of Group 11 (Previously Group Ib).- Trace Elements of Group 12 (Previously Group IIb).- Trace Elements of Group 13 (Previously Group IIIa).- Trace Elements of Group 14 (Previously Group IVa).- Trace Elements of Group 15 (Previously Group Va).- Trace Elements of Group 16 (Previously Group VIa).- Trace Elements of Group 17 (Previously Group VIIa).

/pdf/trace-elements-from-soil-to-human-gyujylwhl8.pdf

Trace Elements From Soil to Human

In Scandinavia 1979, measurements of Hg in air was started at the Swedish west-coast. This site, the Rorvik station, has since then been part of several Swedish and Nordic atmospheric Hg networks. The results from the measurements in these networks clearly demonstrate the existence of a decreasing south-north gradient over Scandinavia. A compilation of available data suggest a decrease in Hg concentrations in air starting in 1990. This coincides with drastically decreased Hg emissions following the closing down of large Hg emitters in the former GDR. Scandinavian measurements of total Hg in precipitation are available from 1987. The coupling between atmospheric Hg in Scandinavia and large continental emission sources, is supported by a clear decreasing south-north gradient and by the fact that the total Hg precipitation data also start to decline around 1990. MeHg in air has recently been measured, but the data set is still too limited to allow trend analysis. The MeHg precipitation data set is much larger, but a rather unclear south-north gardient is present and no coupling to the dramatic changes 1990 in Eastern Europe can be detected. By reviewing the seasonality and long-term changes in our atmospheric Hg data set, together with our Hg/MeHg budget calculation for forested ecosystems and changes in output rates, we try to derive any coupling between the load to a forested ecosystem and the output to surface waters. A lowered export rate of Hg and MeHg over time is indicated in catchment studies in south-western Sweden. However, it is not yet possible to statistically confirm the coupling between input and ouput fluxes of Hg/MeHg from a forested catchment.

Terrestrial Mercury and Methylmercury Budgets for Scandinavia

Removal of gaseous mercury from air using a gold coated denuder

Airsheds and Watersheds

Distribution of persistent organic pollutants and mercury in freshwater ecosystems under changing climate conditions

. Passive air samplers (PASs), which provide time-averaged concentrations of
gaseous mercury over the timescale of weeks to months, are promising for
filling a gap in the monitoring of atmospheric mercury worldwide. Their
usefulness will depend on their ease of use and robustness under field
conditions, their availability and affordability, and most notably, their
ability to provide results of acceptable precision and accuracy. Here we
describe a comparative evaluation of three PASs with respect to their
ability to precisely and accurately record atmospheric background mercury
concentrations at sites in both southern Italy and southern Ontario, Canada. The study includes the CNR-PAS with gold nanoparticles as a sorbent, developed by the Italian National Research Council, the IVL-PAS using an activated carbon-coated disk, developed by the Swedish Environmental Research Institute, and the MerPAS® using a sulfur-impregnated activated carbon sorbent, developed at the University of Toronto and commercialized by Tekran. Detection limits are deduced from the variability in the amount of mercury quantified in more than 20 field blank
samples for each PAS. Analytical and sampling precision is quantified
through 22 triplicate deployments for each PAS, ranging in duration from 2 to 12 weeks. Accuracy and bias are assessed through comparison with
gaseous elemental mercury concentrations recorded by Tekran 2537 automated
mercury analyzers operating alongside the PASs at both locations. The
performance of the PASs was significantly better in Italy, with all of them
providing concentrations that are not significantly different from the
average concentrations of the Tekran 2537 instruments. In Canada, where
weather conditions were much harsher and more variable during the February
through April deployment period, there are differences amongst the PASs. At both sites, the MerPAS® is currently the most sensitive, precise, and accurate among the three PASs. A key reason for this is the larger size and the radial configuration of the
MerPAS®, which results in lower blank levels relative to the sequestered amounts of mercury when compared to the other two PASs, which rely on axial diffusion geometries. Since blank correction becomes relatively smaller with longer deployments, performance tends to be closer amongst the PASs during deployments of 8 and 12 weeks.

/pdf/a-field-intercomparison-of-three-passive-air-samplers-for-30399ah6af.pdf

John Munthe

Papers

Terrestrial Mercury and Methylmercury Budgets for Scandinavia

Removal of gaseous mercury from air using a gold coated denuder

Airsheds and Watersheds

Distribution of persistent organic pollutants and mercury in freshwater ecosystems under changing climate conditions

A field intercomparison of three passive air samplers for gaseous mercury in ambient air