Page 463 - Air pollution and greenhouse gases from basic concepts to engineering applications for air emission control

444 14 Indoor Air Quality

The plot over time is shown in Fig. 14.4.

In addition to the analytical models above, there are a variety of computation
fluid dynamics (CFD) models that can be employed for the predication of indoor air
quality and indoor air pollutant concentrations. Readers are recommended to learn
these specialized models from other publications including those listed in the
Reference section [10–20].

14.5 Practice Problems

1. Minimum ventilation requirement is the __________ value of the ventilation
requirements based on sensible heat balance, moisture balance, and pollutant
balance.
a. maximum
b. minimum
c. average
d. arbitrary
2. While you were cooking using gas burners in your kitchen, the measured
concentrations of CO and CO 2 were 10 and 3500 ppmv, respectively. Is the air
quality in your cooking environment acceptable based on these two pollutants
only? (Given: the TLV’s for CO and CO 2 are 25 and 5000 ppmv, respectively).

a. Yes, because the CO concentration is below the corresponding TLV.
b. No, because the CO 2 concentration is below the corresponding TLV.
c. Yes, because the normalized TLV is below unit.
d. No, because the normalized TLV is above unit.
3. In a Class 1 clean room, the measured total particle concentration is 9 particles/
3
3
m for particles larger than 0.1 μm and 3 particle/m for particles larger than
0.2 μm. Does this cleanroom meet the Class 1 criteria?
3
4. In a large auditorium with a ventilation rate of 6 m /s, the carbon dioxide
concentrations in the exhaust air and supply air are 800 and 400 ppmv,
respectively. The specific volume of exhaust and supply air are 0.82 and
3
3
0.78 m /kg dry air, respectively. The building has an air volume of 8,000 m ,
and the air inside is assumed to be completely mixed. In a power failure, all
exhaust fans are stopped, and there are 1000 people inside, each generates a heat
of 200 W. Assume there is no air exchange between the inside and outside of the
auditorium. How long it will take the CO 2 to reach the ceiling threshold value of
5,000 ppmv after the power failure.
5. There are 30 students in a classroom, each student produce 120 W of sensible
heat and 100 g of water vapour per hour (or 70 W latent heat). The room air
temperature is 20 °C and the specific volume and a relative humidity of 50 %.