Air pollution dispersion modeling is the mathematical simulation of how air pollutant disperse in the ambient atmosphere. It is performed with computer programs, called dispersion models, that solve the mathematical equations and algorithms which simulate the pollutant dispersion
The dispersion models are used to estimate or to predict the downwind concentration of air pollutants emitted from emission sources such as industrial plants and vehicular traffic.
Such models are important to governmental agencies tasked with protecting and managing the ambient air quality.The models are typically employed to determine whether existing or proposed new industrial facilities are or will be in compliance with the National Ambient Air Quality Standards (NAAQS) in the United States and similar standards in other nations. The models also serve to assist in the design of effective control strategies to reduce emissions of harmful air pollutants.
- The dispersion models require the input of data which includes:
- Meteorological conditions such as wind speed and direction, the amount of atmospheric turbulence (as characterized by what is referred to as the stability class), the ambient air temperature and the height to the bottom of any temperature inversion that may be present aloft.
- Emissions parameters such as source location and height, source vent stack diameter and exit velocity, exit temperature and mass flow rate.
- Terrain elevations at the source location and at the receptor location.
- The location, height and width of any obstructions (such as buildings or other structures) in the path of the gaseous emission plume.
Many of the modern, advanced dispersion modeling programs include a pre-processor module for the input of meteorological and other data, and many also include a post-processor module for graphing the output data and/or plotting the area impacted by the air pollutants on maps. Currently, the