The Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) inorganic aerosol sub-model has been implemented in the Global Environmental Multiscale – Modeling Air Quality and Chemistry (GEM-MACH) air quality model. MOSAIC includes metal cation reactions and is a non-equilibrium, double-moment scheme that conserves aerosol number. Compared to the current aerosol sub-model, MOSAIC produces a more accurate size distribution and aerosol number concentration. It also improves the simulated nitrate and ammonium distribution. This work serves to expand the capacity of GEM-MACH for chemistry and weather coupling.

This paper introduces the Multi-Compartment Mercury (Hg) Modeling and Analysis Project (MCHgMAP) aimed at informing the effectiveness evaluations of two multilateral environmental agreements: the Minamata Convention on Mercury and the Convention on Long-Range Transboundary Air Pollution. The experimental design exploits a variety of models (atmospheric, land, oceanic ,and multimedia mass balance models) to assess the short- and long-term influences of anthropogenic Hg releases into the environment.

Accurate simulation of tropical cyclones (TCs) is essential to understanding their behavior in a changing climate. One way this is accomplished is through model intercomparison projects, where results from multiple climate models are analyzed to provide benchmark solutions for the wider climate modeling community. This study describes and analyzes the previously developed TC test case for nine climate models in an intercomparison project, providing solutions that aid in model development.

Absorbing particles like black carbon can be coated with other matter. How much radiation these particles absorb depends on the coating thickness. The removal of these particles by clouds and rain depends on the coating composition. These effects are important for both climate and air quality. We implement a more detailed representation of these particles in an air quality model which accounts for both coating thickness and composition. We find a significant effect on particle concentrations.

An assessment of mercury levels in air and deposition in the Athabasca oil sands region (AOSR) in Northern Alberta, Canada, was conducted to investigate the contribution of Hg emitted from oil sands activities to the surrounding landscape using a 3D process-based Hg model in 2012–2015. Oil sands Hg emissions are found to be important sources of Hg contamination to the local landscape in proximity to the processing activities, particularly in wintertime.