In Canada, the Ministry of the Environment has established strict regulations for pollutant emissions and odor concentration levels. Therefore, commercial biofilters have been installed throughout the province of Ontario to limit contaminant emissions. In this study, the pollution dispersion of the following facilities will be studied and described: 2.1.1 Toronto: the type of industry is that of printed circuit boards, this facility located in a large area of ​​Toronto, and emits mainly volatile organic compounds ( VOCs) ), which present multiple environmental problems if released into the atmosphere2. These compounds are known as “ozone precursors” because of their tendency to react with other compounds such as nitrogen oxides (NOx) to produce ground-level ozone and thus many toxic oxides. Consequentially; VOCs have been regulated at the federal, state, and local levels6. Many health problems such as anemia, irritation of the eyes, nose or skin, and headaches can occur as a result of exceeding the permissible concentration limit of VOCs in the air which is… according to… Additionally, overexposure to These odors could also lead to health problems. For example, overexposure to glycol ethers can cause birth defects and cancer.17 For this reason, a commercial biofilter was installed at this facility in 2000 to control VOC emissions with a removal capacity of 7500 cfm. This biofilter system has two types of wood-based media: organic (Biomix) and synthetic (BIOSORBEN). Sharfdeen et al. (2002) reported that the removal efficiency of these media reached 94% and 99%.182.1.2. Hickson: Meat processing plant is the type of industry located in southwestern Ontario, Hickson. Although the rendering industry has a positive and significant influence...... middle of paper ...... on many factors such as wind speed, effective stack height and atmospheric conditions. This model is based on stable assumptions, which are: (1) the emission rate from the source is constant for a minimum average period (i.e. 1 hour); (2) wind speed is constant in both time and elevation; (3) the pollutant is conservative and not subject to decay and chemical reaction; and (4) the terrain is relatively flat and open. 5.2.2.1 Gaussian Distribution Equation: The first part of this study is to estimate the dispersion of pollutants using the Gaussian equation. This equation (1)* depends on two dispersion parameters (i.e. σy and σz) which are functions of wind speed, temperate climate and cloud cover. In other words, they can be estimated based on five different stability classifications which are stable, unstable, neutral, conditionally unstable or conditionally stable.5,13.