Toxics Use Reduction Institute Inhalation Exposure to Nanoparticles Michael J. Ellenbecker, Sc.D., CIH Toxics Use Reduction Institute University of Massachusetts.

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

LOWELL

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

So

cie

tal I

mp

ac

t a

nd

Ou

trea

ch

Create Nanotemplates:Design, Manufacture

And Functionalize

Use Templates in High Rate Nanomanufacturing

Testbeds: Memory DevicesAnd Biosensor

Re

liab

ility

& D

efe

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 zoneDetecting Locations22 inches distance

Source ConcentraionDetection Location3 inches distance- 1st port

Fugitive SourcesDetecting Locations8 inches distance - 3rd port

Fugitive Sources/ SourceDetecting Locations8 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 pa

rtic

le/c

m3 ]

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]

No

rma

lize

d P

art

icle

Nu

mb

er

Co

nc

en

tra

tio

n

[pa

rtic

le/c

m3 ]

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]

Par

ticle

Num

ber C

once

ntra

tion

dN/d

log

Dp

[10

5 p

artic

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