Dr. Candace SJ Tsai

September 11, 2012

OEL Workshop 2012

Manufacturing facility/R&D

Pilot scale facility/ Chem lab

Clean room

Facilities associated with Center for High-rate Nanomanufacturing

Background level- baseline concentration

Above baseline

Below baseline

After adjust / modify controls and practices

? NO exposure?

Why do we measure? Measure worker exposure to nanomaterials for Check-up and evaluation Epidemiological study, medical surveillance

Seek solution? Evaluate efficacy of controls to reduce exposure

What do we measure? Measure number, surface area, volume and mass concentrations. Identify particle size, composition and morphology.

5 TSI Fast Mobility Particle Spectrometer (FMPS)

TSI Aerodynamic Particle Sizer Spectrometer (APS)

Electrostatic Precipitator

Source: CJ. Tsai et al. ES&T 2012

Aerosol counters - SMPS - FMPS - CPC - Dust track - p-track - Surface area counter

Aerosol collection tools - Filter sampler - Electrostatic precipitator - Thermal precipitator - Impactor

Different…. o Metric? o Concentration magnitude o Size distribution o Collecting duration

Different…. o Collection efficiency o Collecting duration

Source: Asbach et al., JNR, 2009

At different instrument settings

Compare 4 mobility sizers

Source: Jeong and Evans, Aerosol Sci Tech, 2009

Conc. FMPS > SMPS

TEM

SEM

Energy Dispersive Spectroscopy Analysis (EDS), elemental composition

Carbon analysis, total, organic, and elemental carbon

Airborne CNT released from CNT synthesis

Instrument cost is high

Various samplers being used

Various sample analysis

Time consuming

Standard Operation Procedure (SOP) for exposure measurement? Harmonize methodology used for exposure measurement.

Particle 2

0

500

1,000

1,500

2,000

2,500

0 1 2 3 4 5 6 7 8 9 10

Fe Ka Cu Kb 1

Fe Kb 1

Cu Ka

CNT Product Carbon filament, cluster, iron-encapsulated particles

Elemental response from Iron catalyst

Iron and carbon

0.E+00

1.E+06

2.E+06

3.E+06

4.E+06

5.E+06

6.E+06

7.E+06

8.E+06

1 10 100 1,000 10,000 100,000

Diameter, Dp[nm]

Pa

rtic

le n

um

be

r co

nce

ntr

atio

n 1

dN

/dlo

g D

p [ p

art

icle

/cm

3]

0

10

20

30

40

50

60

70

80

90

100

Pa

rtic

le n

um

be

r co

nce

ntr

atio

n 1

dN

/dlo

g D

p [p

art

icle

/cm

3]

L temp-A L temp-B H temp-B

L temp-A L temp-B H temp-B

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1 10 100 1000

Diameter, Dp [nm]

Part

icle

mass c

oncentr

atio

n

dM

/dlo

gD

p [µ

g/m

³]Tsai et al., ES&T 2009

Number conc.

Mass conc.

Compare to in vivo study of Fe2O3 (<200nm) (Sotiriou et al., 2011) Total conc. 2-3 x 105 particle/cm3

Mass conc. 100-200 g/m3 Cause increased relative reactive oxygen species (ROS) in lungs (in vivo chemiluminescence (IVCL) 60 times higher), oxidative stress (11-fold) was present in the heart.

1 g/m3

Exposure concentration:

Alumina oxide 1,000 particle/cm3 during handling

particle diameter is 100 nm density of 3,600 kg/m3 The estimated mass concentration is 2 µg/m3

For 12,000 particle/cm3 , 200 nm mass concentration would be 180 µg/m3

Nanosilver 150 nm, mass concentration is 120 µg/m3

(Tsai 2009)

The lowest concentration for in vivo study is about 100 µg/m3 (Gangwal

2011)

Manufacturing facility/R&D

Pilot scale facility/ Chem lab

Clean room

Facilities associated with Center for High-rate Nanomanufacturing

From instrument uses, e.g. conc. measurements, aerosol collection.

Workplace conditions, control variables, worker practices.

Questions? What data/ information need to be documented ? How much detailed information needs to be documented?

What to be measured on site is not what to be studied for

biological response.

If sampler can be combined with biological assays and

provide dose response.

Develop IH in field direct reading instruments with SOP.

Acknowledgement NSF Nanoscale Science and Engineering Centers Program

(Award no. NSF-0425826)

THANK YOU !!