Assume that an average classroom is 8 m deep, 10 m wide, and 3

m high. Smoking one cigarette releases approximately 0.10 grams of particulates into the air.

(a) If the air in the room initially contains 50 g/m 3 of particulates, how many cigarettes must be

smoked to raise the concentration to the legal limit of 150 g/m 3 ? [See Table 9-1, p.584 in the

text, for other air quality "standards."] (b) If ventilation air flows through the classroom at a rate

of 5000 m 3 /hr, how many cigarettes must be smoked per hour to produce a "steady-state"

concentration of 150 g/m 3 in the room?