GAUSSIAN PLUME EQUATION CALCULATION EXAMPLE PROBLEMS EXAMPLE 1 (max ground level concentration) Hydrogen sulfide (H2S) is vented from a stack in a flat rural area that has an effective stack height 50 m. The wind speed is 2.1 m/s at 10 m above ground on a mostly clear night. For an emission rate of 0.05 g/s determine the maximum ground level concentration on the plume centerline downwind from the stack in ug/m? and the distance from the source, where this concentration occurs. (Use the appropriate graph in the handout for calculating max concentration and distance to max concentration.) EXAMPLE 2 (Estimate effective stack height): A power plant continuously releases a plume. Stack height is 70 m, stack diameter is 5 m, exit velocity is 25 m/s, exit temperature is 398 K, ambient temperature is 298K. If wind speed is 20 kin/h at the top of the stack a) how high is the plume 200m downwind of the stack for neutral conditions? b) if there is a ground inversion layer 150 m thick and wind is 10km/hr, will the plume penetrate the inversion layer? Assume temperature increases 0.3 C through the 150 m of the inversion layer. (See handout .pdf, page second to last Table 18.4For a) use Briggs neutral and unstable: for b) Briggs stable get the potential temperature gradient from Table 18.5, last page of handout) EXAMPLE 3 (application of GPE equation) An existing power plant located in an industrial town, causes a SO? concentration of 70 ug/m?, at a ground level receptor, 800 m downwind from the facility, when northerly wind speed is 2 m/s at 10 m above the ground with a class F atmospheric stability. Another facility is proposed to be located 100 m to the west of the first plant. It will combust coal that contains 3% by mass sulfur. The new plant has an effective stack height of 40 m. Assume 95% of the sulfur in the coal is converted to that is then oxidized to SQ2 and that the new facility has control equipment that will remove 60% by mass of SO2 before the exhaust gas is emitted in the atmosphere. Estimate the rate of coal combustion at the new facility that would cause the concentration of SQ2 to become equal to 80 g/m, at the initial receptor we considered for the same atmospheric conditions described above. Give your answer in kg coal/hr. (1) Use the simple GPE with one reflective boundary. (2) Notice this problem specifies Briggs urban conditions and stability F. Read dispersion coefficients from the respective Tables in the handout