assessment of personal exposure to airborne institut für ...€¦ · christof asbach 9 accuracy...

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

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”


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


Personal monitorsh

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Plenary presentation by Rapahël de Thoury on Thursday morning at 8 am


Lesson 1:Size matters


Size matters

FMPS SMPS Personal Samplers/Monitors

Miniaturization

What do we need to compromise?


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


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


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)


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)


Lesson 2:Wearing of the instruments


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)


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)


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



Ratio

LD

SA

Part

ecto

r

During sitting

0,8

1,0


Ra

tio

LD

SA

Pa

rte

cto

r

0,8

1,0

1,2 4th run3rd run1st run 2nd run

During walking clockwise



miniDiSC results


NaCl 28 nm NaCl 82 nm

0,8

1,0



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


Lesson 3:Unexpected artefacts


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)


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


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)



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!



Lesson 4:Issues related to personal sampling


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


Pressure drop of „nano-samplers“

p can be overcome by personal pumps

BUT: battery time is reduced, full shift measurement may not be possible


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)


Lesson 5:Field studies


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


IUTA colleagues, equipped with personal monitors

miniDiSC and/or Partector

PartectorSampling inlet

75 cm long sampling tubes


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


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


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


Thanks for funding these lessons


Lessons learned!

Thank you for your attention

assessment of personal exposure to airborne institut für ...€¦ · christof asbach 9 accuracy...

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