Consider an area-source box model for air pollution above a peninsula of land (see Figure P7.49). The length of the box is 15km, its width is 80km, and a radiation inversion restricts mixing to 15m. Wind is blowing clean air into the long dimension of the box at 0.5m/s. Between 4 and 6PM there are 250,000 vehicles on the road, each being driven 40km and each emitting 4g/km of CO. FIGURE P7.49 (a) Find the average rate of CO emissions during this two-hour period (gCO/sperm2 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 the box. (c) If the windspeed is 0 , use (7.58) to derive a relationship between CO and time and use it to find the CO over the peninsula at 6PM