You are looking at a new 600 ft3 studio apartment next to a busy roadway. during your visit, you notice an air duct that circulates outside air into the room. knowing that mercury is emitted from vehicles, you are concerned about the level of mercury in the apartment during rush hour. doing your background research, you figure out that the osha ceiling limit for mercury is 100 μg/m3.

a.) what is the steady-state concentration of mercury in the apartment if the ventilation air flow rate in the room is 500 ft3/min and the incoming air has a concentration of mercury of 100 mg/m3? how does the mercury concentration depend on the ventilation flowrate? present a complete mass balance solution. hint: if there is no air outflow, what would happen to the pressure in the apartment?

b.) in the overnight hours, mercury concentrations drop to zero as fresh air is circulated through the apartment. how long after the morning rush hour do you have before you need to worry about the mercury concentration in the apartment? present a complete mass balance solution.

c.) make a plot of the mercury concentration versus time. your plot should include sufficiently long times to show the concentration increasing to at least 99% of its steady-state value. ensure your plot contains x and y labels (with units, if applicable). describe the plot in words.