Potential inhalation exposure and containment efficiency when using hoods for
handling nanoparticles
Candace Su-Jung Tsai
NSF Center for High-rate Nanomanufacturing (CHN), University of Massachusetts Lowell, One University
Avenue, Lowell, Massachusetts 01854.
Author for correspondence (E-mail: candace.umass@gmail.com )
Supporting Information
Statistical analysis using Pearson correlation
The number (N) of data points used for analysis is 32, which are 32 concentration data, 1 per diameter channel,
plotting one concentration distribution profile. The correlation coefficient is a number between +1 and -1, and
is interpreted as the magnitude and direction of the association between two variables. The “magnitude” is the
strength of the correlation. The closer the correlation is to either +1 or -1, the stronger the correlation. If the
correlation is 0 or very close to zero, there is no association between the two variables. The “direction” of the
correlation interprets how the two variables are related. A positive  value means that the two variables have a
positive relationship (as one increases, the other also increases), while a negative  value means that the two
variables have a negative relationship (as one increases, the other decreases). The p-value measured the
significance of the correlation; a p-value less than 0.05 means the correlation is significant.
(a)
Baseline Concentration- Regular Condition
9,000
3
dN/dlog Dp [ particle/cm ]
Particle number concentration1
Bio cabinet 1
8,000
Bio cabinet 2
7,000
Powder enclosure 1
Powder enclosure 2
6,000
5,000
4,000
3,000
2,000
1,000
0
1
10
100
1000
Diameter, Dp[nm]
(b)
Baseline Concentration- Alternative Condition
Bio cabinet 1
dN/dlog Dp [ particle/cm ]
8,000
3
Particle number concentration1
9,000
Powder enclosure 1
7,000
Powder enclosure 2
6,000
5,000
4,000
3,000
2,000
1,000
0
1
10
100
1000
Diameter, Dp[nm]
Figure S1: Baseline concentration at breathing zone of four hoods for (a) regular condition experiments and (b)
alternative condition for both transferring and pouring experiments.
Table S1. Results of Pearson correlation coefficient of breathing zone corrected concentration distribution: (a)
Associations among four hoods during transferring at regular and alternative condition; (b) Associations
between transferring and pouring tasks at regular and alternative conditions for four hoods.
(a)
Correlation of Four Hoods during Transferring
Bio Cabinet 1
Bio Cabinet 2
Powder Enclosure 1
Powder Enclosure 2
Condition
R
A
R
A
R
A
R
A
Bio Cabinet 1
1
1
-0.87
0.38
0.49
0.59
0.76
-0.48
Bio Cabinet 2
-0.87
0.38
1
1
-0.17
-0.14
-0.56
-0.89
Powder Enclosure 1
0.49
0.59
-0.17
-0.14
1
1
0.15
-0.02
Powder Enclosure 2
0.76
-0.48
-0.56
-0.89
0.15
-0.02
1
1
(b)
Correlation of Transferring and Pouring
R
A
Bio Cabinet 1
0.97
0.77
Bio Cabinet 2
0.74
0.74
Powder Enclosure 1
0.97
0.97
Powder Enclosure 2
0.97
0.97
R: Regular condition; A: Alternative condition.
All correlations are significant at the 0.01 level (2-tailed).
Table S2. Calculation of mass concentration of airborne alumina
Number Conc.
Particle Diameter
Particle Volume Conc.
Mass Conc.
Mass Conc.
particles/cm3
nm
m3/cm3
kg/cm3
µg/m3
49
49
261
780
970
836
810
890
800
550
350
202
87
4
0
29
72
114
133
130
132
138
164
211
240
250
231
180
138
100
75
58
Sum of
6
7
8
9
10
12
14
17
19
22
25
29
34
39
45
52
60
70
80
93
107
124
143
166
191
220
255
295
340
390
453
523
6 - 523
5.54E-24
8.80E-24
7.00E-23
2.98E-22
5.08E-22
7.56E-22
1.16E-21
2.29E-21
2.87E-21
3.07E-21
2.86E-21
2.58E-21
1.79E-21
1.24E-22
0.00E+00
2.14E-21
8.14E-21
2.05E-20
3.57E-20
5.48E-20
8.47E-20
1.38E-19
2.51E-19
5.05E-19
8.76E-19
1.39E-18
2.01E-18
2.42E-18
2.84E-18
3.11E-18
3.65E-18
4.34E-18
2.E-20
3.E-20
3.E-19
1.E-18
2.E-18
3.E-18
4.E-18
8.E-18
1.E-17
1.E-17
1.E-17
9.E-18
6.E-18
4.E-19
0.E+00
8.E-18
3.E-17
7.E-17
1.E-16
2.E-16
3.E-16
5.E-16
9.E-16
2.E-15
3.E-15
5.E-15
7.E-15
9.E-15
1.E-14
1.E-14
1.E-14
2.E-14
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.1
0.2
0.3
0.5
0.9
1.8
3.2
5.0
7.2
8.7
10.2
11.2
13.1
15.6
78.3
Case 2
12,000
200
5.03E-17
2.E-13
181.0
Case 3
10
626
1.28E-18
5.E-15
4.6
Case 1
Note: Density of alumina oxide particles is 3,600 kg/m 3