assessment of personal exposure to airborne institut für ...€¦ · christof asbach 9 accuracy...
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Institut für Energie- und
Umwelttechnik e.V.
Assessment of personal
exposure to airborne
nanomaterials - Lessons
learned during the project
Air Quality & Filtration
Christof AsbachA. M. Todea, A. Meyer-Plath, B. Simonow, M. van Tongeren, L. MacCalman, M. Fierz,
D. Dahmann, I. Iavicoli, S. Clavaguera
Fifth nanoSafeConferenceGrenoble, November 8th, 2016
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Christof Asbach www.nanoindex.eu 2
Thorstein Veblen (1857–1929)
“The outcome of any serious research can only be to make
two questions grow where only one question grew before”
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Christof Asbach www.nanoindex.eu 3
Assessment of Individual Exposure to manufactured nanomaterials by means of
personal monitors and samplersFunded in the framework of the SIINN Era-Net program
in EU-FP7
Duration: June 2013 – May 2016
7 partners + 1 subcontractor from 5 countries
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Christof Asbach www.nanoindex.eu 4
Personal monitorsh
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Christof Asbach www.nanoindex.eu 5
Personal samplersh
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Plenary presentation by Rapahël de Thoury on Thursday morning at 8 am
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Christof Asbach www.nanoindex.eu 6
Lesson 1:Size matters
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Christof Asbach www.nanoindex.eu 7
Size matters
FMPS SMPS Personal Samplers/Monitors
Miniaturization
What do we need to compromise?
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Christof Asbach www.nanoindex.eu 8
Compromise
Instrument Metric(s) Size range [nm] Time resolution Size resolution
SMPS Size distribution 2.5 – 1,000 nm30 s to several
minutesUp to 128 ch. per decade
FMPS Size distribution 5.6 – 560 nm 1 s16 ch. per
decade
Personalmonitors
Number, LDSA and/or mean
size20 -400 nm 1 – 16 s None
Personalsamplers
Mass conc., chemical comp.
< d50
Typ. several hours (full shift)
None
Compromise: Information wealth and size resolution
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Christof Asbach www.nanoindex.eu 9
Accuracy and comparability
10 100 1000
10-4
10-3
10-2
10-1
Particle diameter dp [nm]
miniDiSC 1
miniDiSC 2
miniDiSC 3
LD
SA
pe
r p
art
icle
[µ
m²]
Todea et al., J. Aerosol Sci. 89: 96-109, 2015
Accuracy
Todea et al., Sci. Total Environ. (close to submission)
-100
-80
-60
-40
-20
0
20
40
60
80
100
120
n=35
n=35n=78n=114
nanoTracer
4-7
nanoTracer
1-3Partector
miniDiSC/
DiSCmini
Aerosols within instrument size range
LD
SA
De
via
tio
n fro
m r
efe
ren
ce
[%
]
Comparability
Compromise: Accuracy and comparability of personal diffusion charging instruments for particles and
agglomerates around ± 30% for 20 nm ≤ dp ≤ 400 nm
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Christof Asbach www.nanoindex.eu 10
Nu
mb
er
Co
ncen
trati
on
PU
FP
C100
(1/c
m³) NaCl Carbon
0.0 2.5x104
5.0x104
0.0
2.5x104
5.0x104
82 nm
DEHS
0 1x105
2x105
3x105
4x105
0
1x105
2x105
3x105
4x105
35 nm
92 nm
0 1x105
2x105
3x105
4x105
0
1x105
2x105
3x105
4x105
111 nm
233 nm
Number Concentration Reference UCPC 3776 (1/cm³)
Comparability of a personal CPC
Personal CPC ± 10% accurate, except for highly hydrophobic particles
Asbach et al., Aerosol Air Qual. Res. (submitted)
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Christof Asbach www.nanoindex.eu 11
Relative error for fibres
-100
-75
-50
-25
0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
375
400
425
450
475
500
CPC.TSI_2_BAuA CPC_2_BAuA DiscMini_1_BAuA MiniDisc_12_IUTA
Device
Re
lative
Err
or
to S
MP
S_
3_
BA
uA
Co
nce
ntr
atio
n in
%
Device CPC.TSI_2_BAuA CPC_2_BAuA DiscMini_1_BAuA MiniDisc_12_IUTA
CPC.TSI_2 CPC_2 DiSCMini_1 MiniDisc_12
0%
-100%
100%
200%
300%
400%
500%R
ela
tive e
rror
Data courtesy of A. Meyer-Plath, BAuA
See posters S2-P8 by Meyer-Plath et al. and S2-P9 by Simonow et al. for more information
(both on Thursday)
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Christof Asbach www.nanoindex.eu 12
Lesson 2:Wearing of the instruments
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Christof Asbach www.nanoindex.eu 13
Comparability of the monitors at field-like conditions
C2
B
C1
DE
F
G
T P rh Q
A1 Aerosol generation (atomizer, spark generator or flame generator), drying and neutralization
A2 Optional ULPA background filterB Wind tunnel, approximately 20 m long, 0.7 m diameterC1 Measurement chamber, approximately 20 m³C2 T-shaped sampling trainD BlowerE Exhaust filterF ExhaustG Control room for flow rate Q, measurement of temperature T,
pressure P and relative humidity rh in measurement chamber C1
A1
A2
Partector miniDiSC/DiSCmini
NaCl Test Aerosols (30 & 80 nm)
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Christof Asbach www.nanoindex.eu 14
Test sequence
TablePerson 1
Person 2
7 m/s3.5 m/s2 m/s Aerosol in
Aerosol out
7 m/s
Walkingclockwise
Walkingcounter-clockwise
<0.5 m/s
3.2 m
2.6
m
Sequence:• 5 min sitting• 5 min walking clockwise• 2 min sitting• 5 min walking counter
clockwise• 2 min sitting• 5 min assembly &
disassembly of MPG II dust sampler
Asbach et al., Environ. Sci. Nano (revision submitted)
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Christof Asbach www.nanoindex.eu 15
0,8
1,0
1,2 4th run2nd run 3rd run1st run
ratio left/right ratio left/table ratio right/table
Ratio
LD
SA
Part
ecto
r
NaCl 28 nm
0,8
1,0
1,2 4th run3rd run2nd run1st run
Ra
tio
LD
SA
Pa
rte
cto
r
NaCl 82 nm
Partector results
0,8
1,0
1,2 4th run2nd run 3rd run1st run
ratio left/right ratio left/table ratio right/table
Ratio
LD
SA
Part
ecto
r
During sitting
0,8
1,0
1,2 4th run2nd run 3rd run1st run
Ra
tio
LD
SA
Pa
rte
cto
r
0,8
1,0
1,2 4th run3rd run1st run 2nd run
During walking clockwise
Asbach et al., Environ. Sci. Nano (revision submitted)
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Christof Asbach www.nanoindex.eu 16
miniDiSC results
Asbach et al., Environ. Sci. Nano (revision submitted)
NaCl 28 nm NaCl 82 nm
0,8
1,0
1,2 4th run2nd run 3rd run1st run
ratio left/right ratio left/table ratio right/table
Ratio
LD
SA
Part
ecto
r
1
2
0.3
3rd run 4th run2nd run1st run
Ra
tio
LD
SA
min
iDiS
C
1
2
0.3
4th run3rd run2nd run1st run
During sitting
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Christof Asbach www.nanoindex.eu 17
Lesson 3:Unexpected artefacts
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Christof Asbach www.nanoindex.eu 18
Observed artefacts during personal measurements
3
3,5
4
4,5
5
5,5
6
6,5
0
50
100
150
200
250
300
350
400
450
500
09:50:24 11:02:24 12:14:24 13:26:24 14:38:24 15:50:24 17:02:24
Co
ron
a V
olt
age
[kV
]
LDSA
co
nce
ntr
atio
n [
µm
²/cm
³]
Time
miniDiSC 1 (personal) LDSA miniDiSC 2 (table) LDSA DiSCmini (personal) LDSA
miniDiSC 1 corona voltage miniDiSC 2 corona voltage DiSCmini corona voltage
1st run 2nd run 3rd run 4th runbreak(tubes
disconnected)
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Christof Asbach www.nanoindex.eu 19
Effect of sampling tube
-60
-40
-20
0
20
1 2 31 2NSAMPartectorminiDiSC
TSI tubing new
LD
SA
/ U
coro
na
Devia
tion fro
m m
easure
ment w
ithout tu
bin
g [%
]
LDSA
Ucor
-60
-40
-20
0
20
1 2 31 2NSAMPartectorminiDiSC
LD
SA
/ U
coro
na
De
via
tio
n f
rom
me
asu
rem
en
t w
ith
ou
t tu
bin
g [
%]
TSI tubing aged
LDSA
Ucor
• Instruments sampling through 75 cm conductive silicone tubing• Strong effect on both measured concentration and corona voltage
New TSI Aged TSI
Asbach et al., Aerosol Sci. Technol. (accepted) http://dx.doi.org/10.1080/02786826.2016.1241858
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Christof Asbach www.nanoindex.eu 20
Siloxanes from new TSI tube
NEU
1) Hexamethyldisiloxane (222,46 g/mol) > 1mg/ml
3) Octamethylcyclotetrasiloxan e(236,53 g/mol) > 1 mg/ml
6) Dodecamethylcyclopentasiloxane (296,62 g/mol) < 0,1 mg/ml
7) Dodecamethylcyclohexasiloxane (444,92 g/mol) not calibr.
8) Tetradecamethylhexasiloxane (458,99 g/mol) not calibr.
(1)
(3)
(6)
(7)
(8)
Asbach et al., Aerosol Sci. Technol. (accepted) http://dx.doi.org/10.1080/02786826.2016.1241858
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Christof Asbach www.nanoindex.eu 21
Effect of sampling tube
-5
0
5
10
1 2 1 2 3NSAMPartectorminiDiSC
Tygon tubing
LD
SA
/ U
coro
na
De
via
tio
n fro
m m
ea
sure
me
nt w
itho
ut tu
bin
g [%
]
LDSA
Ucor
Tygon
The choice of sampling tube material can have a
drastic (unexpected) effect on the measurement with
personal monitors!
Asbach et al., Aerosol Sci. Technol. (accepted) http://dx.doi.org/10.1080/02786826.2016.1241858
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Christof Asbach www.nanoindex.eu 22
Lesson 4:Issues related to personal sampling
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Christof Asbach www.nanoindex.eu 23
Correct sampling time
Gravimetric Analysis:
Must be long enough to collect enough material (depends on sensitivity of the scale)
Chemical Speciation
Must be long enough to collect enough material (depends on LOD of analyzer)
Electron Microscopic Analysis
Must be within a certain time window:
- Short enough to avoid agglomeration on substrate
- Long enough to keep analysis effort reasonable
Difficult, as sampling time depends on size and concentration
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Christof Asbach www.nanoindex.eu 24
Pressure drop of „nano-samplers“
p can be overcome by personal pumps
BUT: battery time is reduced, full shift measurement may not be possible
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Christof Asbach www.nanoindex.eu 25
Sampling or monitoring?
There is no clear answer!
Sampling….
• …if chemical composition shall be determined
• …if particle morphology (e.g. fibre) is of interest
• …if (average) mass concentration shall be determined
Monitoring…
• …if number or LDSA concentrations shall be determined
• …if high time resolution is needed
No single instrument can do it all!A combination of sampler and monitor may be the best
compromise in given situations
See poster S2-P2 by Simon Clavaguera et al for more information
(on Thursday)
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Christof Asbach www.nanoindex.eu 26
Lesson 5:Field studies
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Christof Asbach www.nanoindex.eu 27
Field measurements at IUTA pilot plant
• Pilot plant for theproduction of upto several kg/day
• Here: productionof Fe doped SiO2
• Measurement during synthesis, bagging andcleaning
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Christof Asbach www.nanoindex.eu 28
IUTA colleagues, equipped with personal monitors
miniDiSC and/or Partector
PartectorSampling inlet
75 cm long sampling tubes
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Christof Asbach www.nanoindex.eu 29
Time series of LDSA concentration
12:09:00 13:09:00 14:09:00 15:09:000
50
100
150
200
250
300
personal measurement
strong local source
side by side
comparison
personal measurement
no local source
FMPS (far field)
partector (personal)
LD
SA
co
nce
ntr
atio
n [
µm
²/cm
³]
Time
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Christof Asbach www.nanoindex.eu 30
Correlation personal – far field
10 100
10
100
strong local source
LD
SA
pers
on
al [µ
m²/
cm
³]
LDSA far field [µm²/cm³]
no local source
side by side
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Christof Asbach www.nanoindex.eu 33
Lessons learned?
“The outcome of any serious research can only be to make
two questions grow where only one question grew before”
• nanoIndEx taught us several lessons, many of them with direct practical implications
• If we keep them in mind, the new samplers and monitors can be readily applied in field studies
• For more information, please refer to the Guidance Document and our website http://www.nanoindex.eu
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Christof Asbach www.nanoindex.eu 34
Thanks for funding these lessons
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Christof Asbach www.nanoindex.eu 35
Lessons learned!
Thank you for your attention