2) Air quality can be a significant problem in refrigerated warehouses since these buildings are designed to be "air tight". In addition, the insulation in these facilities can release small amounts of formaldehyde into the air within the warehouse (at a rate G in units of mg/hr ): In order to minimize the accumulation of formaldehyde, the warehouse can be equipped with an air-handling system. The system pumps air at a constant flow rate q out of the building. In this case a 2-stage air handling system is used, with the air flow split into 2 separate streams. 70% of the air is passed through a charcoal filtration system to remove formaldehyde, with the treated air returned directly to the building. The charcoal filtration system has an efficiency of 95%, i.e., the concentration of formaldehyde in the stream returned to the warehouse is 5% of that entering the filtration system. The other 30% of the air flow is passed through a heat exchanger and then vented to the atmosphere. Fresh (cooled) air is added to the warehouse to maintain constant volume. a) Draw a sketch of the system, carefully labeling all streams. b) Derive an expression for the formaldehyde concentration in the warehouse as a function of time assuming that the volume of the warehouse (V), the total air flow rate through the air handling system (q), the formaldehyde release rate (G), and the air density are all constant. The initial formaldehyde concentration in the warehouse is Co. c) Evaluate the formaldehyde concentration in the warehouse after 1 week if Co=0.01mg/L,G=2mg/hr,q=1.5L/min, and V=10,000L