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