At a gathering of 30 people in a room 6m x 9m x 3m half of the people are smoking an average of 3 cigarettes per hour. Each cigarette releases 2.4 mg of formaldehyde. The air exchanges five times an hour. Assuming that the outdoor formaldehyde concentration is neglible, calculate the steady-state concentration in the air inside the room. Does the concentration exceed the concentration (100 ppbv) considered to be the level of concern?