A large laboratory of 1000 m3 is equipped with a ventilation system.

This ventilation system provides safe, comfortable, breathable environments for all lab users and to minimize exposures to hazardous air contaminants. It is also designed to remove toxicant from the point of generation in the laboratory to the outside air. The ventilated air is discharged at a volumetric flow rate of 600 m3 /min at 25ºC and 1 atm, which can also be assumed as temperature and pressure of the laboratory air. A gas leak from a reactor in the laboratory caused the room to be contaminated with 1.5 mol of carbon monoxide (CO). Health hazard is defined if the mol fraction of CO in the laboratory is larger than 0.7 ppm (7 x 10-7 ). Assume the CO behave as an ideal gas. Consider air in the laboratory is perfectly homogenized, what is differential CO balance, letting N be the total moles of air and x the mol fraction of CO in the laboratory. Provide the initial condition.