. We evaluate four high-resolution model simulations of pollutant
emissions, chemical transformation, and downwind transport for the Athabasca
oil sands using the Global Environmental Multiscale – Modelling Air-quality
and Chemistry (GEM-MACH) model, and compare model results with surface
monitoring network and aircraft observations of multiple pollutants, for
simulations spanning a time period corresponding to an aircraft measurement
campaign in the summer of 2013. We have focussed here on the impact of
different representations of the model's aerosol size distribution and
plume-rise parameterization on model results. The use of a more finely resolved representation of the aerosol size
distribution was found to have a significant impact on model performance,
reducing the magnitude of the original surface PM 2.5 negative biases
32 %, from − 2.62 to − 1.72  µ g m −3 . We compared model predictions of SO2 , NO2 , and speciated
particulate matter concentrations from simulations employing the commonly
used Briggs (1984) plume-rise algorithms to redistribute emissions from large
stacks, with stack plume observations. As in our companion paper (Gordon et
al., 2017), we found that Briggs algorithms
based on estimates of atmospheric stability at the stack height resulted in
under-predictions of plume rise, with 116 out of 176 test cases falling below
the model : observation 1 : 2 line, 59 cases falling within a factor of 2
of the observed plume heights, and an average model plume height of 289 m
compared to an average observed plume height of 822 m. We used a
high-resolution meteorological model to confirm the presence of significant
horizontal heterogeneity in the local meteorological conditions driving plume
rise. Using these simulated meteorological conditions at the stack locations,
we found that a layered buoyancy approach for estimating plume rise in stable
to neutral atmospheres, coupled with the assumption of free rise in
convectively unstable atmospheres, resulted in much better model performance
relative to observations (124 out of 176 cases falling within a factor of 2
of the observed plume height, with 69 of these cases above and 55 of these
cases below the 1 : 1 line and within a factor of 2 of observed values).
This is in contrast to our companion paper, wherein this layered approach
(driven by meteorological observations not co-located with the stacks) showed
a relatively modest impact on predicted plume heights. Persistent issues with
over-fumigation of plumes in the model were linked to a more rapid decrease
in simulated temperature with increasing height than was observed. This in
turn may have led to overestimates of near-surface diffusivity, resulting in
excessive fumigation.

/pdf/a-chemical-transport-model-study-of-plume-rise-and-particle-2ira4j0rse.pdf

A chemical transport model study of plume-rise and particle size distribution for the Athabasca oil sands

A CFD analysis of the pollutant dispersion from cooling towers with various configurations in the lower region of atmospheric boundary layer.

. Artificial rain is explored as a remedy to climate change caused farmland drought and bushfires. Increasing the ion density in the open air is an efficient way to generate charged nuclei from atmospheric aerosols and induce precipitation or eliminate fog. Here we report on the development of the large commercial installation scale atmospheric ion generator based on corona plasma discharges, experimental monitoring and numerical modeling of the parameters and range of the atmospheric ions, and application of the generated ions to produce charged aerosols and induce precipitation at a scale of a large cloud chamber. The coverage area of the ions generated by the large corona discharge installation with the 7.2 km long wire electrode and applied voltage of −90 kV is studied under prevailing weather conditions including wind direction and speed. By synergizing over 300 000 localized corona discharge points, we demonstrate a substantial decrease of the decay of ions compared to a single corona discharge point in the open air, leading to a large-scale (30 m × 23 m × 90 m) ion coverage. Once aerosols combine with the generated ions, charged nuclei are produced. The higher wind speed has led to the larger areas covered by the plasma generated ions. The cloud chamber experiments (relative humidity 130 ± 10 %) suggest that the charged aerosols generated by ions with the density of ~ 104/cm3 can accelerate the settlement of moisture by 38 %. These results are promising for the development of large-scale installations for the effective localized control of atmospheric phenomena.

/pdf/large-scale-ion-generation-for-precipitation-of-atmospheric-1v0fu6ulzu.pdf

Large-scale ion generation for precipitation of atmospheric aerosols

In this paper, the k–e renormalization group (RNG) turbulence model is used to simulate the flow and dispersion of pollutants emitted from a source at the top of a cubic building under neut...

https://journals.ametsoc.org/doi/pdf/10.1175/JAMC-D-19-0045.1

Numerical and Wind Tunnel Simulation Studies of the Flow Field and Pollutant Diffusion around a Building under Neutral and Stable Atmospheric Stratifications

Majid Shafipour Motlagh

Papers

Direct effect of atmospheric turbulence on plume rise in a neutral atmosphere

New plume rise modeling in a turbulent atmosphere via hybrid RANS-LES numerical simulation