As a hard working student you decide that you need to relax at the world renowned Ferguson Day Spa. After your massage you decide to use one of their ``therapeutic'' hot tubs. After some investigating, you find that the aqueous concentration of chloroform and trichloroethylene (TCE) in the hot tub water is 50 μg/L and 5 μg/L, respectively.
Chloroform and other trihalomethanes (THMs) are formed in water that is disinfected with chlorine. THMs are suspected carcinogens. Human exposure occurs when the water is ingested either directly or in a food or beverage product. Human exposure also occurs when THMs volatilize out of the water into the air and are inhaled, and when the skin is in contact with water or air containing THMs, especially during bathing. Wallace (1997) provides a recent summary of studies investigating chloroform intake.
To mathematically predict human exposure to consumer products, RIVM has developed the software model ConsExpo. The most recent version of ConsExpo is version 4.1.
Answer the following questions using the three-zone indoor air quality model tutorial.
What layout in a real home might be realistically represented by three zones?
Adjust the volumes and air flows for the three zones to represent a layout you have in mind. How much exposure might a person in one of the adjacent rooms to a smoker receive in the layout you have chosen?
Using the two-zone mass balance model interactive tutorial, answer the following questions about particle dynamics in two rooms that are connected by an open or closed doorway.
Under what conditions can concentrations in Room #2 exceed those in Room #1?
What parameters affect the distance in time between the concentration peaks in each room?
How realistic do you think this model in describing air pollutant levels in two separate rooms of a real home due to smoking or some other pollution source? What added features would make it more realistic?
The book "Exposure Analysis" (533p), edited by Wayne R. Ott, Anne C. Steinemann, and Lance A. Wallace, was published in 2007 by CRC Press, Boca Raton (Taylor & Francis Group). It is the first complete resource in the emerging scientific discipline of exposure analysis.
