A coal-fired power plant releases SO2 at a rate of 1500 g/s. The wind speed at the top of the stack is 4 m/s. Calculate the SO2 concentration at a point 4 km down wind and 0.2 km perpendicular to the plume centerline from the stack under overcast condition. Assuming the atmosphere stability is class D. Stack parameters: Atmosphere conditions: Height = 100.0 m Pressure = 95.0 kPa Diameter = 1.2 m Temperature = 25.0 oC Exit velocity = 8 m/s Temperature = 315 oC For class D stability, sy = ax0.894, a = 68; sz = cxd + f, c = 44.5, d = 0.516, f = -13