This work is ongoing and is being extended to support homeland security related studies in other parts of Manhattan.
The results of CFD simulations can both be directly used to better understand specific case studies as well as be used to support the development of more simplified algorithms that may be generally applied. Detailed CFD simulations make it possible to safely explore potential scenarios in support of preparedness, location of monitoring instrumentation and better understanding air measurements.
Pollutant transport and dispersion in the ambient environment is being simulated. Plans have been initiated to develop methods to interface with indoor air quality.
Future wind tunnel and field studies should play a critical role in supporting CFD developments by providing opportunities for CFD simulation evaluation and demonstration of reliability. The process should be iterative in that a better CFD model provides better guidance for collecting better measurements.
Even the best conceivable field measurement study will have very few data relative to the detailed structure of air flow and pollutant dispersion within the complex built urban environments. Therefore application of CFD simulations is critical to being able to understand pollutant transport and dispersion within urban building environments, and consequently critical in support of homeland security. Jump to main content.
Pollutant Dispersion in Built Environment | SpringerLink
Contact Us. Description: There is presently much focus on Homeland Security and the need to understand how potential sources of toxic material are transported and dispersed in the urban environment. Organization: U. Air pollution is the introduction of particulates, biological molecules, or other harmful materials into Earth's atmosphere, causing disease, death to humans, damage to other living organisms such as food crops, or the natural or built environment.
Air pollution may come from anthropogenic or natural sources. Dispersion refers to what happens to the pollution during and after its introduction; understanding this may help in identifying and controlling it. Air pollution dispersion has become the focus of environmental conservationists and governmental environmental protection agencies local, state, province and national of many countries which have adopted and used much of the terminology of this field in their laws and regulations regarding air pollution control.
Air pollution emission plume — flow of pollutant in the form of vapor or smoke released into the air.
CFD simulation of micro-scale pollutant dispersion in the built environment
Plumes are of considerable importance in the atmospheric dispersion modelling of air pollution. There are three primary types of air pollution emission plumes :.
There are five types of air pollution dispersion models, as well as some hybrids of the five types: . Effect of turbulence on dispersion — turbulence increases the entrainment and mixing of unpolluted air into the plume and thereby acts to reduce the concentration of pollutants in the plume i.
It is therefore important to categorize the amount of atmospheric turbulence present at any given time. This type of dispersion is scale dependent.
There is no limit on the size on mixing motions in the atmosphere and therefore bigger clouds will experience larger and stronger mixing motions. And hence, this type of dispersion is scale dependent. Pasquill atmospheric stability classes — oldest and, for a great many years, the most commonly used method of categorizing the amount of atmospheric turbulence present was the method developed by Pasquill in Advanced air pollution dispersion models — they do not categorize atmospheric turbulence by using the simple meteorological parameters commonly used in defining the six Pasquill classes as shown in Table 2 above.
The more advanced models use some form of Monin-Obukhov similarity theory.