In many instances, the results of an Air Dispersion Modeling study will be compared to legislated ambient or ground level air pollution criteria to determine the compliance status of a facility.

What is Air Dispersion Modeling?
Air Dispersion Modeling predicts how pollutants are dispersed in the atmosphere from different pollution sources taking into account building influences, topography, meteorology, downwind distances, and other factors.

Dispersion Modeling is often a requirement for attaining Certificates of Approval and Air Permits. LEHDER offers extensive modeling expertise across a wide variety of sectors.  Pro-active self-assessment is an area where LEHDER excels, allowing clients to identify potential problems before they arise, and to employ effective solution development.

LEHDER conducts modeling using the following models:
	Reg. 346 Model (Run 308)
	AERMOD
	ISCSTPrime
	SCREEN3

Computer models are a relatively inexpensive and expedient means of providing air quality information. For example, models can be used to predict the future concentration of a particular pollutant after the implementation of a new pollution control program.

The results of the modeling are then used to estimate the effectiveness of the control program and whether it is worth the cost of implementation. Because of their ability to evaluate a variety of options for managing air quality, dispersion models are an important planning tool.