1. (40 pts) A company has a stack that emits a hazardous air pollutant. The ground mass concentration directly downwind of the plume sometimes exceeds the safe limit (call it cj,safe ) and the Department of Environmental Protection (DEP) is requiring a correction to this situation. The company decides to look into building a taller stack, rather than investing in a more sophisticated and very expensive APCS. They hire you as a consultant to calculate how tall the new stack would have to be in order to satisfy DEP. (a) Generate an equation to determine the stack height hs required such that, for the reflecting ground case, the ground level concentration on the ground directly downwind (y=0 and z=0) does not exceed the safe level at any location along the ground. Note: This problem does not involve numbers or units. Rather, generate an equation for hs as a function of additional thermal plume height h due to buoyancy, dispersion coefficients y and z (which vary with downwind distance x of course and depend on the atmospheric stability class), wind speed U, source strength mj,s, and safe mass concentration limit cj,safe. Your answer should be an equation for hs as a function of only the above listed variables. (b) Repeat for the absorbing ground case. (c) Discuss. Is this a good solution for the company's problem? For the environment