0. Nanomaterials: BAuA Research on Exposure Assessment
Dr. Rolf Packroff
Scientific Director of the Division „Hazardous substances and biological agents"
BAuA – Federal Institute for Occupational Safety and Health, Dortmund (Germany)

1. BAuA Nanosafety Research
measurement and characterization of particles
toxikological and risk assessment
control strategies/ governance
toxicity screening
(cyto-TP)
test chamber for
measurement devices
dustiness testing
(shaker)
safety cabinet

2. BAuA Survey on production and use of nanomaterials in Germany (2011)
TOP 5 nanomaterials: industrial scale
1. amorphous silica (SiO2)
2. titanium dioxide (TiO2)
3. crystalline silica / quartz (SiO2)
4. polymers / composites
5. carbon black
Scale of use
TOP 5 nanomaterials: lab scale
1. multiwalled carbon nano tubes (MWCNT)
2. titanium dioxide (TiO2)
3. silver (Ag)
4. gold (Au)
5. organic nanomaterials
No. of nanomaterials
Questionaire to "nano" companies and research instutions,
454 returns, 194 nanomaterials, ~ 50% from research institutions

3. Thermophoretic Precipitation Principle
Gas Flow Channel
Warm Silicon Wafer
Cold Silicon Wafer
Aerosol
higher
momentum
gas molecules
lower
Flow
Sealing
For thermophoresis, a warm plate provides gas molecules with additional momentum to push nanoparticles towards an opposing cold plate.
SEM-based morphological and statistical analysis of individual NPs on the cold sampling wafer surface

4. BAuA’s Personal Thermophoretic Sampler (TP)
Battery and microcontroller
in a backpack
BAuA’s thermophoretic sampler TP4 has been developed in a cooperation of BAuA and IUTA. It consists of a sampling head and an additional unit, called aspirator, which supplies energy and controls the temperature gradient and air flow. The geometry of the BAuA sampling head has been studied by numerical simulations with regard to its thermophoretic sampling efficiency for nanoparticles.
Sampling head in front
Opened TP sampler with
sampling head, flow sensor
and thermocouple amplifiers
Remote Control and Logging

5. Other measurement devices
monitoring
CPC
SMPS
DiSCmini
sampling
NAS
filter TP
PGP-FAP
← personal measurements →

6. Current field study: Extrusion of CNT (EU project: NanoIndex))
stationary und personal measurements
near and far field exposure
background measurements
metrics: particles/cm³

7. Comparison of Measurement Devices (ongoing) (EU project: NanoIndex))
400 l exposure chamber
targeted generation of high-rate nanofiber aerosols
characterization of aerosols
practical safety testing

8. Significant increase over background concentration detected?
Tier 1:
Information Gathering
Tiered Approach
Tier 2:
Basic Exposure Assessment
... to an Exposure Measurement and Assessment of Nanoscale Aerosols Released from Engineered Nanomaterials in Workplace Operations (2011)
Tier 3:
Expert Exposure Assessment
Significant increase over background concentration detected?
P/cm³ (d < 6 g/cm³)

9. Reference: Particle Background in European Cities
Number of
particles
< nm
P / cm³
G. Löschau „Partikelanzahl in verkehrsnaher Außenluft“
P. Aalto et al „Aerosol particle number concentration measurement in five European cities…“ J Air Waste Manag Assoc Aug;55(8):

10. Dustiness Testing
Dustiness is an important material property to assess exposure of man and environment in the lifecycle of nano and advanced materials
The BAuA Shaker Method facilitates testing of dustiness and morphological characterisation of released particles
Most investigated nanomaterials have a low dustiness!
There a exemptions. Currently we have no model approach to explain them.
Carbon nano tubes span a broad range of dustiness. A predictive principle is lacking, too.
image: BAuA/Fox/Völkner

11. Carbon nano tubes (CNT): a broad span of dustiness
n-Tec MWCNT
Number of particles
Nanothinx NTX3
Arry ARSM003
Vortrag wird begonnen mit SEM-Bildern, die die Vielfalt der unterschiedlichen Morphologien der NM zeigen
Baytubes C150P
Test No.
from: CarboLifeCycle (founded by BMBF)
SEM images: BAuA
baua_vorlagen.ppt

12. Morphological Characterization
image: BAuA/Fox/Völkner

13. nano titanium dioxide (TiO2)
SEM image: BAuA
1 µm = nm

14. nano silver (Ag)
SEM images: BAuA

15. nano zinc oxide (ZnO)
1 µm = nm
SEM image: BAuA

16. entangled carbon nano tubes (CNT)
SEM images: BAuA

17. rigid carbon nano tubes (MWCNT-7)
SEM image: BAuA

18. soot particles (+ table salt crystal)

19. welding fume
2 µm

20. nanosilver + background

21. Lessons learned (I) Workplace sampling techniques ...
... for respirable particles are applicable and helpful for nanomaterial workplace measurements
... for asbestos have to be modified for determination of CNT and other nanofibres
Workplace monitoring techniques ...
... allow screening against background particle concentration to decide on further need for risk assessment
... can help to improve performance of closed systems or LEV
baua_vorlagen.ppt

22. Lessons learned (II) Dustiness testing ...
... is a simple and cheap way to estimate a nanomaterial´s potential for release of respirable particles
... is under adaption to nanomaterials (ISO)
Morphological characterisation
... is costly and therefore restricted to research and large instituations / firms
... offers important information for risk charakterisation
... is currently to only way to distinguish between rigid and non-rigid fibres

23. Thank you
baua.bund.de