Air pollution

37) Consider an area-source box model for air pollution above a peninsula of land. the length of the box is 15 km, its width is 80 km, and a radiation inversion restricts mixing to 15 m. Wind is blowing clean air into the long dimention of the box at 0.5 m/s. Between 4 and 6 pm there are 250,000 vehicles on the road, each being driven 40 km and each emitting 4 g/km of CO.

a) Find the average rate of CO emissions during this two-hour period (g CO/s per m^2 of land)

b) Estimate the concentration of CO at 6pm if there was no CO in the air at 4pm. Assume that CO is conservative and that there is instantaneous and complete mixing in thh box

c) if the windspeed is zero, use the formula to derive relationship between CO and time and use it to find the CO over the peninsula at 6pm

(formula: LWH(dC/dt) = Qs*L*W + W*H*u*Cin - W* H*u*C
where C = pollutant concentration in the airshed, mg/m^3
          Cin = concentration in the incoming air, mg/m^3
          Qs = emission rate per unit area, mg/m^2-s
          H  = mixing height, m
          L  =  length of airshed, m
          W  = width of airshed, m
          u  = average windspeed against one edge of the box, m/s)