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
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