The owner of a smoky bar in a warm climate relies on natural exchange between the bar and outside to keep smoke levels manageable in the bar (below 50 microgram/m). Smokers account for a smoke PM10 source of 0.5 mg/s in the bar. If the diffusivity between bar and outside is 10 m/s, what will be steady PM10 concentration in the bar? How would the concentration in the bar change if they enlarged it by increasing depth to 30 m without changing the opening to outside? Would smoke PM10 levels still be manageable? [12.5 microgram/m; 25.0 microgram/m]