- 5 -
Formula (3) is substituted into formula (2) and each stage's 50 % separated dynamic particle
diameter d
p50
is obtained by the following formula.
ρ
π
μ
CQ
D
N
d
c
p
4
18
3
50
50
×
Ψ
=
C
ND
c
3
7
10
71
.
7
×
×
=
−
···············
(4)
However, Q = 28.317 cm
3
/min = 28.3 L/min
ρ
= 1
g/cm
3
The geometric particle diameter can be obtained on the basis of
ρ
/
2
p
d
.
In Andersen Sampler, the particle size ranges shown in Fig. 1 are obtained when the aerosol
particle diameter collected in each stage is applied using formula (4). The particle size distribution
has been confirmed to precisely match the results of experiments using standard particles with a
known diameter.
Fig. 1 Structure of AN-200 Andersen Sampler and Particle Size
Bronchus
Bronchus
Gasket
Stage
Collection plate
Airflow
11
μ
m min.
Backup filter
0.65 to 1.1
μ
m
1.1 to 2.1
μ
m
2.1 to 3.3
μ
m
3.3 to 4.7
μ
m
4.7 to 7.0
μ
m
7.0 to 11
μ
m
0.43 to 0.65
μ
m
0.43
μ
m max.
Trachea
Throat
Alveolus
Alveolus
Alveolus
