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Plume spread at the ground due to gravity is also simulated by a method (Anfossi et al., 2009), based on Eidsvik (1980). STACKS (The Netherlands) – A Gaussian plume dispersion model for point and area buoyant plumes to be used over flat terrain on a local scale. It includes building effects, NO 2 chemistry and plume depletion by deposition ...
The Gaussian air pollutant dispersion equation (discussed above) requires the input of H which is the pollutant plume's centerline height above ground level—and H is the sum of H s (the actual physical height of the pollutant plume's emission source point) plus ΔH (the plume rise due to the plume's buoyancy).
For example, such a regulation might limit the concentration of NOx to 55 ppmv in a dry combustion exhaust gas corrected to 3 volume percent O 2. As another example, a regulation might limit the concentration of particulate matter to 0.1 grain per standard cubic foot (i.e., scf) of dry exhaust gas corrected to 12 volume percent CO 2.
The AERMOD atmospheric dispersion modeling system is an integrated system that includes three modules: [1] [2] [3]. Graphic display of Aermod output. A steady-state dispersion model designed for short-range (up to 50 kilometers) dispersion of direct air pollutant emissions primarily from stationary industrial sources.
A plume may also have a higher density than air if the plume is at a much lower temperature than the air. For example, a plume of evaporated gaseous methane from an accidental release of liquefied natural gas (LNG) may be as cold as −161 °C (−258 °F). Passive or neutral plumes – Plumes which are neither lighter or heavier than air.
If a gaseous emission sample is analyzed and found to contain water vapor and a pollutant concentration of say 40 ppmv, then 40 ppmv should be designated as the "wet basis" pollutant concentration. The following equation can be used to correct the measured "wet basis" concentration to a " dry basis " concentration:
The subjects covered in the book include atmospheric turbulence and stability classes, buoyant plume rise, Gaussian dispersion calculations and modeling, time-averaged concentrations, wind velocity profiles, fumigations, trapped plumes and gas flare stack plumes. The constraints and assumptions involved in the basic equations are fully explained.
Plume shapes can be influenced by flow in the ambient fluid (for example, if local wind blowing in the same direction as the plume results in a co-flowing jet). This usually causes a plume which has initially been 'buoyancy-dominated' to become 'momentum-dominated' (this transition is usually predicted by a dimensionless number called the ...