Plume heights

Aircraft can take vertical temperature soundings and can measure air pollutant and tracer concentrations and turbulence intensity. Airborne lidar can measure plume heights, and integrating nephelometers can determine particle size distributions. 

The final effective plume height H, in m, is stack height plus plume rise. Where buoyancy dominates, the horizontal distance Xf from the stack to where the final plume rise occurs is assumed to be at 3.5 , where x is the horizontal distance, in km, at which atmospheric turbulence begins to dominate entrainment. 

For low-buoyancy plumes in stable conditions, plume height due to momentum is given by... 

One major item remains before we can apply the dispersion methodology to elevated emission sources, namely plume height elevation or rise. Once the plume rise has been determined, diffusion analyses based on the classical Gaussian diffusion model may be used to determine the ground-level concentration of the pollutant. Comparison with the applicable standards may then be made to demonstrate compliance with a legal discharge standard. 

Plume height is based on the assumed F stability and 2.5 m/s wind speed, and the dispersion parameter (o, ) incorporates the effects of buoyancy induced dispersion. If x , is less than 200 m, then no shoreline fumigation calculation is made, since the plume may still be influenced by transitional rise and its interaction with the TIBL is more difficult to model. 

According to aircraft measurements within the USSR, the plume height exceeded 1200 m on 27 April and on subsequent days, the plume height did not exceed 200-400 m. The volatile elements iodine and caesium, were detectable at greater altitudes (6-9 km), with traces also in the lower stratosphere (Jaworowski et al., 1988). The refractory elements, such as cerium, zirconium, neptunium and strontium, were for the most part of significance only in local deposition within the USSR. 

A small industrial furnace emits 0.8 m3/sec of exhaust gases at a temperature of 80°C. Outside air temperature is 10°C, and wind speed is 2 m/sec. The stack is 20 m tall, with a diameter of 40 cm. What is the plume height at the edge of the property 30 m downwind ... 

Therefore, 30 m downwind, the plume height above the ground can be estimated as the stack height plus the plume rise ... 

Fendell, F.E. (1985) Observation of Plume Heights and Ash Transport in Large Fires, Appendix 5-1 of from The Effects on the Atmosphere of a Major Nuclear Exchange, (Carrier, G.F., Chairman) National Academy Press, Washington, D.C., pp. 97-100, 1985. 

When the plume has reached its final height, h becomes independent of x, and the effective plume height can be written as... 

D (either two horizontal dimensions—typical for shallow layer models—or downwind distance or travel time and plume height—typical for plume trajectory models—are independent variables)... 

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