Aerosol Chemistry and Physics - Aerosols: Measurement, Dosimetry, and Health Effects - page 165

2.0

Clovis aerodynamic diameter
Clovis optical diameter
Richmond aerodynamic diameter
Richmond optical diameter

1.5

1.0

0.5

0.0

10

0.1 1

FIGURE 6.14 Particle penetration in two dwellings as measured by both optical and aerodynamic particle
size instruments. (From Thatcher, T.L. et al., Aerosol Sci. Technol ., 37, 847, 2003.)

The dwelling labeled “Richmond” is an older structure with a much larger overall leakage area than
the “Clovis” dwelling. As can be seen in Figure 6.2, the tighter structure had lower overall penetra-
tion factors and particles larger than ∼3 μm had penetration factors as low as ∼0.3. In contrast,
penetration factors for the Richmond structure were close to 1 as a function particle size, with the
lowest penetration factor equal to ∼0.8.

6.5.3 i ndoor a erosol d ePosition r ates
Indoor aerosol deposition rates as a function of particle size have been developed both empirically
and the results summarized by Thatcher et al. (2002) as shown in Figure 6.15. An important feature
of these curves is the strong dependence of the deposition decay rates on particle size. There is a
minimum deposition rate for particle diameters between 0.1 and 0.2 μm (k ∼ 0.03 h −1 under quiescent
conditions), but the rates increase rapidly for particles both larger (k ∼ 0.3 h −1 and k ∼ 18 h −1 for 1.5
and 5 μm diameter particles, respectively) and smaller (k ∼ 0.15 h −1 for 0.06 μm diameter particles).

Current work (min/max) Mosley et al. (2001), low/med fan

Mosley et al. (2001), high fan
Thatcher and layton (1995)
Vette et al. (2001)
Xu et al. (1994), no fans
Xu et al. (1994), with fans

Abt et al. (2000)
Abt et al. (1995)
Fogh et al. (1997), unfurnished
Fogh et al. (1997), furnished
Long et al. (2001)

10

1

0.1

Model: Lai and Nazaroff (2000)
S/V=4/m, u * =3 (cm s -1 ), sg=2.5
S/V=2/m, u * =0.3 (cm s -1 ), sg=1.0
10

0.01
0.01 0.1 1

Particle diameter (µm)

FIGURE 6.15 Particle deposition loss rates as reported in several studies. Current work refers to Thatcher
et al. (2002), from which the igure originated. The model results cover a range of surface-to-volume ratios,
internal air motion (friction velocities), and particle densities.