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4 Sample Evaluation Method
4-1
Mass Measurement
The mass is calculated from the difference between the mass of the collection plates before
sampling and after sampling. For more accurate measurement, a precision balance (minimum
scale line of 0.01 mg or less) needs to be used. Measurement in a thermostatic chamber is
more desirable when a precision balance is used. Store collection plates and backup filters in a
desiccator with desiccant. After storing them for approximately 24 hours, measure the mass,
measure the mass of aerosol in each stage, and plot the cumulative percentages on lognormal
probability paper by the procedure described in 4-2 to use the graph as a particle size
distribution table.
4-2 Particle Size Distribution Example and How Standard Deviation
Is Expressed
Stage No.
particle size (
μ
m)
Collected amount (mg)
%
Cumulative %
0 11
min.
0.06
0.1 100.0
1
11 max. (7.0 to 11)
0.24
0.4
99.9
2
7.0 max. (4.7 to 7.0)
0.84
1.4
99.5
3
4.7 max. (3.3 to 4.7)
2.34
3.8
98.1
4
3.3 max. (2.1 to 3.3)
5.88
9.5
94.3
5
2.1 max. (1.1 to 2.1)
20.64
33.3
84.8
6
1.1 max. (0.65 to 1.1)
16.51
26.7
51.6
7
0.65 max. (0.43 to 0.65) 10.00 16.2
24.9
Backup filter
0.43 max.
5.39
8.7
8.7
Note: A calibration table is provided with each equipment. Each flowmeter is calibrated
using a wet gas meter.
