Simplified Calculation Method for Dispersion

As noted earlier, atmospheric dispersion of a pollutant largely depends on  

meteorological conditions such as ambient temperature, wind speed, time of day, insulation, cloud coverage all of which may be classified as atmospheric stabihty parameters, and 

pollutant stack emission parameters such as velocity, temperature and the molecular weight of discharging vapors. 

Any stack should be designed based on a knowledge of prevailing meteorological conditions and stack emission criteria based on years of operating 

Critical GLC s can usually be calculated based on a unstable atmosphere, thus enabling the designer to determine a worst case scenario. For any given day, typical atmospheric stabihty data can usually be obtained from a local weather bureau, or may be estimated from the so-called Pasquill chart for the appropriate Atmospheric Stability Class (refer to Table 1). 

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