Consider the air over a 17 city to be a box 100 km on a side that reaches up to an altitude of 1.0 km. clean air is blowing into the box along one of its sides with a speed of 4 m/s. sup- pose an air pollutant with reaction rate k 10.0 kg/s. find the steady-state if the windspeed in problem 17 suddenly drops pollutants two hours later 0.20/hr is emitted into the box at a total rate of concentration if the air is assumed to be completely mixed to 1 m/s, estimate the concentration of 18