Assessment of personal exposure to airborne nanomaterials - Lessons learned during the project

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1 Christof Asbach A. M. Todea, A. Meyer-Plath, B. Simonow, M. van Tongeren, L. MacCalman, M. Fierz, D. Dahmann, I. Iavicoli, S. Clavaguera Assessment of personal exposure to airborne nanomaterials - Lessons learned during the project Institut für Energie- und Umwelttechnik e.v. Air Quality & Filtration Fifth nanosafeconference Grenoble, November 8 th, 2016

2 The outcome of any serious research can only be to make two questions grow where only one question grew before Thorstein Veblen ( ) Christof Asbach 2

3 Assessment of Individual Exposure to manufactured nanomaterials by means of personal monitors and samplers Funded in the framework of the SIINN Era-Net program in EU-FP7 Duration: June 2013 May partners + 1 subcontractor from 5 countries Christof Asbach 3

4 uploads/2016/06/nano_brosch%c3%bcre.pdf Personal monitors Christof Asbach 4

http://www.nanoindex.eu/wp-content/ uploads/2016/06/nano_brosch%c3%bcre.

5 uploads/2016/06/nano_brosch%c3%bcre.pdf Personal samplers Plenary presentation by Rapahël de Thoury on Thursday morning at 8 am Christof Asbach 5

6 Lesson 1: Size matters Christof Asbach 6

7 Size matters FMPS SMPS Personal Samplers/Monitors Miniaturization What do we need to compromise? Christof Asbach 7

8 Compromise Instrument Metric(s) Size range [nm] Time resolution Size resolution SMPS Size distribution 2.5 1,000 nm 30 s to several minutes Up to 128 ch. per decade FMPS Size distribution nm 1 s 16 ch. per decade Personal monitors Number, LDSA and/or mean size nm 1 16 s None Personal samplers Mass conc., chemical comp. < d 50 Typ. several hours (full shift) None Compromise: Information wealth and size resolution Christof Asbach 8

Accuracy and comparability Accuracy Comparability 120 Aerosols within instrument size range LDSA per particle [µm²] 10-1 10-2 10-3 10-4 minidisc 1 minidisc 2 minidisc 3 10 100 1000 Particle diameter

9 Accuracy and comparability Accuracy Comparability 120 Aerosols within instrument size range LDSA per particle [µm²] minidisc 1 minidisc 2 minidisc Particle diameter d p [nm] LDSA Deviation from reference [%] n=114 minidisc/ DiSCmini n=78 Partector n=35 nanotracer 1-3 n=35 nanotracer 4-7 Todea et al., J. Aerosol Sci. 89: , 2015 Todea et al., Sci. Total Environ. (close to submission) Compromise: Accuracy and comparability of personal diffusion charging instruments for particles and agglomerates around ± 30% for 20 nm d p 400 nm Christof Asbach 9

10 Number Concentration PUFP C100 (1/cm³) Comparability of a personal CPC 4x10 5 NaCl Carbon 4x10 5 DEHS 3x x nm 3x10 5 2x10 5 1x nm 92 nm 2.5x10 4 2x10 5 1x nm 233 nm 0 0 1x10 5 2x10 5 3x10 5 4x x x x10 5 2x10 5 3x10 5 4x10 5 Number Concentration Reference UCPC 3776 (1/cm³) Asbach et al., Aerosol Air Qual. Res. (submitted) Personal CPC ± 10% accurate, except for highly hydrophobic particles Christof Asbach 10

11 Relative error Relative error for fibres 500% 400% Relative Error to SMPS_3_BAuA Concentration in % 300% See posters % S2-P8 by Meyer-Plath et al. and S P9 by Simonow et al. for more information % 0% -100% Device CPC.TSI_2_BAuA CPC_2_BAuA DiscMini_1_BAuA MiniDisc_12_IUTA (both on Thursday) CPC.TSI_2_BAuA CPC_2_BAuA DiscMini_1_BAuA MiniDisc_12_IUTA Device CPC.TSI_2 CPC_2 DiSCMini_1 MiniDisc_12 Data courtesy of A. Meyer-Plath, BAuA Christof Asbach 11

12 Lesson 2: Wearing of the instruments Christof Asbach 12

Comparability of the monitors at field-like conditions NaCl

A1 Aerosol generation (atomizer, spark generator or flame

background filter B Wind tunnel, approximately 20 m long, 0.

T-shaped sampling train D Blower E Exhaust filter F Exhaust

T, pressure P and relative humidity rh in measurement

13 Comparability of the monitors at field-like conditions NaCl Test Aerosols (30 & 80 nm) B A2 C1 A1 C2 F D E T P rh Q G A1 Aerosol generation (atomizer, spark generator or flame generator), drying and neutralization A2 Optional ULPA background filter B Wind tunnel, approximately 20 m long, 0.7 m diameter C1 Measurement chamber, approximately 20 m³ C2 T-shaped sampling train D Blower E Exhaust filter F Exhaust G Control room for flow rate Q, measurement of temperature T, pressure P and relative humidity rh in measurement chamber C1 Partector minidisc/discmini Christof Asbach 13

14 2.6 m Test sequence 3.2 m 2 m/s 3.5 m/s 7 m/s Aerosol in Person 1 <0.5 m/s Table Person 2 Walking clockwise Walking counterclockwise 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 7 m/s Aerosol out Asbach et al., Environ. Sci. Nano (revision submitted) Christof Asbach 14

15 Partector results During During walking sitting clockwise NaCl 28 nm NaCl 82 nm ratio left/right ratio left/table ratio right/table 1,2 1st 1st run run 2nd 2nd run run 3rd 3rd run run 4th 4th run run 1,2 1st run 2nd run 3rd run 4th run Ratio LDSA Partector 1,0 Ratio LDSA Partector 1,0 0,8 0,8 1st run 2nd run ratio left/right ratio left/table ratio right/table 3rd run 4th run Asbach et al., Environ. Sci. Nano (revision submitted) Christof Asbach 15

16 minidisc results During sitting NaCl 28 nm NaCl 82 nm 2 1st run 2nd run 3rd run 4th run 2 1st run 2nd run 3rd run 4th run Ratio LDSA minidisc st run 2nd run ratio left/right ratio left/table ratio right/table 3rd run 4th run Asbach et al., Environ. Sci. Nano (revision submitted) Christof Asbach 16

17 Lesson 3: Unexpected artefacts Christof Asbach 17

18 Observed artefacts during personal measurements LDSA concentration [µm²/cm³] 450 minidisc 1 (personal) LDSA minidisc 2 (table) LDSA DiSCmini (personal) LDSA 6,5 minidisc 1 corona voltage minidisc 2 corona voltage DiSCmini corona voltage 1st run 2nd run 400 break 3rd run 4th run 6 (tubes disconnected) 5, , Corona Voltage [kv] , :50:24 Christof Asbach 11:02:24 12:14:24 13:26:24 Time 14:38:24 15:50: :02:24 18

Effect of sampling tube Instruments sampling through 75 cm conductive silicone tubing Strong effect on both measured concentration and corona voltage LDSA / U corona Deviation from measurement

19 Effect of sampling tube Instruments sampling through 75 cm conductive silicone tubing Strong effect on both measured concentration and corona voltage LDSA / U corona Deviation from measurement without tubing [%] minidisc 1 2 New TSI TSI tubing new Partector LDSA Ucor NSAM LDSA / U corona Deviation from measurement without tubing [%] minidisc 1 2 Aged TSI tubing TSI aged Partector LDSA Ucor NSAM Asbach et al., Aerosol Sci. Technol. (accepted) Christof Asbach 19

Siloxanes from new TSI tube (3) NEU (7) 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

20 Siloxanes from new TSI tube (3) NEU (7) 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) (6) (8) Asbach et al., Aerosol Sci. Technol. (accepted) Christof Asbach 20

Effect of sampling tube LDSA / U corona Deviation from measurement without tubing [%] 10 5 0-5 Tygon Tygon tubing minidisc Partector 1 2 1 2 3 LDSA Ucor NSAM The choice of sampling tube material can

21 Effect of sampling tube LDSA / U corona Deviation from measurement without tubing [%] Tygon Tygon tubing minidisc Partector LDSA Ucor NSAM 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) Christof Asbach 21

22 Lesson 4: Issues related to personal sampling Christof Asbach 22

Correct sampling time Gravimetric Analysis: Must be long enough to collect enough

enough to collect enough material (depends on LOD of analyzer) Electron

avoid agglomeration on substrate - Long enough to keep analysis effort reasonable

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 Christof Asbach 23

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 Christof Asbach 24

25 Sampling or monitoring? Sampling. There is no clear answer! if chemical composition shall be determined if particle morphology (e.g. fibre) is of interest if (average) mass concentration shall be determined See poster S2-P2 by Simon Clavaguera et al for more information (on Thursday) 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 Christof Asbach 25

26 Lesson 5: Field studies Christof Asbach 26

27 Field measurements at IUTA pilot plant Pilot plant for the production of up to several kg/day Here: production of Fe doped SiO 2 Measurement during synthesis, bagging and cleaning Christof Asbach 27

28 IUTA colleagues, equipped with personal monitors Sampling inlet Partector minidisc and/or Partector 75 cm long sampling tubes Christof Asbach 28

29 Time series of LDSA concentration LDSA concentration [µm²/cm³] personal measurement no local source FMPS (far field) partector (personal) side by side comparison personal measurement strong local source 12:09:00 13:09:00 14:09:00 15:09:00 Time Christof Asbach 29

30 Correlation personal far field strong local source no local source side by side LDSA personal [µm²/cm³] LDSA far field [µm²/cm³] Christof Asbach 30

grow where only one question grew before nanoindex taught us several

in mind, the new samplers and monitors can be readily applied in field

31 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 Christof Asbach 33

32 Thanks for funding these lessons Christof Asbach 34

33 Lessons learned! Thank you for your attention Christof Asbach 35

EXPOSURE ASSESSMENT TO NOAA AT WORKPLACE AN OPPORTUNITY TOWARDS A SAFER AND MORE RESPONSIBLE DEVELOPMENT OF NANOCOMPOSITES: NANOLEAP PROJECT

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