Toxics Use Reduction Institute

Inhalation Exposure to

Nanoparticles

Michael J. Ellenbecker, Sc.D., CIH

Toxics Use Reduction Institute

University of Massachusetts Lowell

Potential for Exposure

• Workers and the general public may be exposed to airborne nanoparticles

– During their manufacture

– During their incorporation into devices

– During their use

– After end-of-life disposal

• Very little is known about the potential for such exposures, and effective measures to control such exposures

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The NSF Nanoscale Science and Engineering Center for High-rate Nanomanufacturing

So

cie

tal Im

pact

an

d O

utr

each

Create Nanotemplates:

Design, ManufactureAnd Functionalize

Use Templates in High

Rate Nanomanufacturing

Testbeds:

Memory Devices

And Biosensor

Reliab

ilit

y &

Defe

cts

, an

d M

od

elin

g

Education and Outreach

SocietalImpact

Collaboration andInteraction

CHN Pathway to

Nanomanufacturing

Potential Exposures

• Nanoparticles– Manufacturing

– Compounding

– Adding powders to liquids

– Particles in liquids

• Chemicals– Adding functionality to C60 and CNT

requires complex chemical reactions

– Nanolithography & other techniques for making templates

Cross-section of alveoli

Shows a very

thin (500 nm)

separation

between

blood and air.

An SEM

image of the

alveoli is

shown in the

inset

Hoet et al. J Nanobiotech 2004.

Regional Lung Deposition

Airborne Nanoparticle Monitoring

TSI Fast Mobility Particle Sizer (FMPS) Spectrometer Model 3091 (TSI)

• 5.6 to 560 nm,

32 channels

• 1 s cycle time

Results: Aerosol Monitoring-Processing

(7) Twin Screw Extruder

Layout of Aerosol Measuring Locations:

Background/Breathing zone

Detecting Locations

22 inches distance Source Concentraion

Detection Location

3 inches distance

- 1st port

Fugitive Sources

Detecting Locations

8 inches distance

- 3rd port

Fugitive Sources/ Source

Detecting Locations

8 inches distance

-2nd port

Results: Aerosol Monitoring-Processing

(7) Twin Screw Extruder

Source Concentration during Feeding 5% Nanoalumina

2.52860

7.99656

0.41996

3.78688

0

1

2

3

4

5

6

7

8

9

1 10 100 1000Diameter [Dp/nm]

Pa

rtic

le n

um

be

r co

nce

ntr

atio

n

dN

/dlo

g D

p [1

05 p

art

icle

/cm

3]

Separate feeder into 1st port-5%NA Separate feeders into 1st and 2nd ports-5%NA

Premix feeder into 1st port-5%NA [Control-ABS] Separate feeders into 1st and 2nd ports

Results: Aerosol Monitoring-Processing

(5) CNT Furnace

Results: Aerosol Monitoring-Processing

(5) CNT Furnace

CNT Furnace Operation - Experimental and Control Data Comparison

0.0E+00

2.0E+06

4.0E+06

6.0E+06

8.0E+06

1.0E+07

1.2E+07

1 10 100 1000Diameter [Dp/nm]

Norm

aliz

ed P

art

icle

Num

ber

Concentr

ation

[part

icle

/cm

3]

Source conc. during CNT grow- detect on hole [Control]- Source conc. during CNT grow- detect on hole

Breathing zone conc. during operation [Control]- Breathing zone conc. during operation

Results: Aerosol Monitoring-Processing

(6) Fullerene Shaking Reaction

Results: Aerosol Monitoring-

Processing(6) Fullerene Shaking Reaction

Fullerene Vibration Device - Source and Breathing Zone Concentration

[Experimental and Control Data Comparison]

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1 10 100 1000

Diameter [Dp/nm]

Pa

rtic

le N

um

be

r C

on

ce

ntr

atio

n

dN

/dlo

g D

p [

105

pa

rtic

le/c

m3]

Source conc during operation [Control] Source conc during operation

Breathing zone conc during operation- 1 meter away [Control] Breathing zone conc during operation- 1 meter away

Respirator Performance

• Recent research suggests that the proper respirator may be highly effective against nanoparticles

– N100 cartridges – 100% efficient for

nanoparticles, as predicted

– N95 cartridges – Pt > 5% for 40 nm particles

at high breathing rates

Filtration Mechanisms

Boltzman Equilibrium Charge

Distribution

• Aerosol particles are charged by random interaction with air ions

• 1 µm particle – 90% charged at any instant

• 40 nm particle – 20% charged at any instant

Air Pollution Control Equipment

• HEPA filters likely to be effective

• Cyclones will not work

• Unanswered questions on the efficacy of fabric filters, electrostatic precipitators, and Venturi scrubbers

Precautionary Principle

• When there is uncertainty, err on the side of precaution

• For nanoparticles, this means we need to reduce exposure to the lowest possible level

• We are working with the various CHN laboratories to identify control strategies to accomplish this