Environmental Engineering Reference
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8
Vapor
Mechanically
generated
7
6
Condensation
5
Nucleation
4
DGV=0.018
σ 3 =1.87
3
2
DGV=0.018
σ 2 =1.8
DGV=0.018
σ 1 =1.6
1
0
0.002
0.01
0.1
1
10
100
Particle diameter, D u (µm)
Nuclei mode
Accumulation mode
Coarse mode
Fine- mode p articles
Coarse-mode particles
FIGURE  23.1  Distribution of particle mean diameter by particle volume for typical outdoor PM aerosol.
DGV: geometric mean diameter by volume (volume mean diameter); σ g : geometric standard deviation. The
circle points to overlap area between particle diameter and source contribution. (From U.S. Environmental
Protection Agency (EPA), Air quality criteria for particulate matter—Third external review draft, EPA
600/P-99/002aC, Report No.: EPA 600/P-99/002aC, Research Triangle Park, NC, 2001.)
0.25
1
Fine particles
D p < 2.5 µm
Nanoparticles
0.2
0.8
D p < 50 nm
Deposition
Ultrafine particles
D p < 100 nm
PM 10
D p < 10 µm
0.15
0.6
Accumulation
mode
0.1
0.4
Nuclei
mode
Coarse
mode
0.05
0.2
0
0
1,000
10,000
1
10
100
Particle diameter (nm)
Mass
Number
Surface
Deposition (alveolar + tracheobronchial)
FIGURE  23.2  Normalized, mass-weighted, and number-weighted particle size distributions and alveolar
deposition from typical diesel exhaust. Note that in this igure “coarse mode” is deined as PM 10-2.5 . (From
Kittelson, D. et al., Measurement of diesel aerosol exposure: A feasibility study, in Health Effects Institute
Special Report-Research Directions to Improve Estimates of Human Exposure and Risk from Diesel Exhaust,
pp. 153-179, April, 2002.)
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