Problem 2 (20 points) Air Pollution: Area-Source Models mixing depth of H (m). CO is emitted in the box at the rate of Q

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Problem 2 20 Points Air Pollution Area Source Models Mixing Depth Of H M Co Is Emitted In The Box At The Rate Of Q 1 (67.08 KiB) Viewed 37 times

Problem 2 (20 points) Air Pollution: Area-Source Models mixing depth of H (m). CO is emitted in the box at the rate of Qs (kg/s). Answer the following Consider a box model for an air shed over a city with equal length and width of L (m) and a questions: (i) (4 points) Winds with no CO blow at velocity u (m/s) against one side of the box. If CO is considered to be conservative, write the steady-state material balance for CO in the air shed by denoting its concentration as c, (kg/m³). (ii) (4 points) Based on the material balance you wrote in (i), provide the expression that gives the CO concentration, c. (kg/m³), in the air shed. (iii) (4 points) Assume now that after steady-state conditions have been reached for the city, the wind speed drops to u/2. Write the unsteady-state material balance for CO in the air shed by denoting its concentration as c (kg/m³). (iv) (4 points) Based on the material balance you wrote in (iii), provide the expression that gives the concentration of CO, cu (kg/m3), after time t (s). (v) (2 points) Draw a graph showing the CO concentration as a function of time based on the expression you found in (iv). On the graph indicate the initial and steady-state CO concentrations. (vi) (2 points) Explain briefly why we need to control the concentration of CO in the atmosphere. In your solution, draw a schematic of the system, state all your assumptions, use only those symbols introduced in the problem, and show details.