8/14/2019 Flagan US China 2009
1/14
Airborne Nanoparticles
Rick Flagan
California Institute of Technology
Pasadena, CA 91125USA
Presented at
Second China-US Workshop on Nanotstructured Materials for Global Energy and
Environmental Challenges
October 17-18, 2009
October 17, 2009
http://find/http://goback/8/14/2019 Flagan US China 2009
2/14
Developing understanding of health impacts of engineered
nanoparticles
Initial understanding was derived from inadvertent emissionse.g., diesel truck nanoparticles
increased adverse pulmonary and cardiovascular health outcomes
among those living within ~100 m of major roadways in US, UK, and
Netherlans
Wheezing and asthma, reduced heart rate variability, blood pressureincrease with extended exposure, etc.
http://find/http://goback/8/14/2019 Flagan US China 2009
3/14
Developing understanding of health impacts of engineered
nanoparticles
Xia et al. Acs Nano (2008) vol. 2 (10) pp. 2121-2134
Availability of engineerednanoparticles is now enablingfundamental mechanistic studiesof health effects
Different nanoparticles exhibit
different modes of action, e.g.,in Nels study:
ZnO2 nanoparticles
translocate across cell
membranes
Dissolution in cytoplasmicmaterial leads to direct
cytotoxic effects
But less soluble TiO2 and
CeO2 did not.
http://find/http://goback/8/14/2019 Flagan US China 2009
4/14
Developing understanding of health impacts of engineered
nanoparticles
Nel and coworkers have deveoeda four-tiered model of healtheffects of particulate exposure(Xia et al. ACS Nano2:2121-2134 (2008))
Boundaries between stages arenot sharp, but provide aframework with which to studyand understand healthconsequences
http://find/http://goback/8/14/2019 Flagan US China 2009
5/14
Differential mobility analysis
http://find/http://goback/8/14/2019 Flagan US China 2009
6/14
Common differential mobility analyzers
Knutson & Whitby (1975)
TSI Long Column DMA
Winkmayr et al. (1992)Vienna DMA
Chen et al. (1998)nanoDMA (TSI)
Zhang et al. (1990) Caltech RDMA
Others:
de la Mora
Takefumi
MSP
Grimm
http://find/http://goback/8/14/2019 Flagan US China 2009
7/14
Nanoparticle exposures in an automobile cabin in heavy
traffic
Zhu et al., Env. Sci. Technol. (2007)
Airborne nanoparticle
concentrations vary rapidlyTransient sources
Rapid coagulation with larger
particles
Rapid, local measurements are
neededNeed personal monitors for
worker exposure
Nanoparticles can be efficientlyremoved by filtration
Pore size is not relevant to
collection of nanoparticles
from gas
Diffusional deposition rather
than sieving
http://find/http://goback/8/14/2019 Flagan US China 2009
8/14
NanoRDMA
Brunelli et al. (2009) Aerosol Sci. Tech. 43: 53-59
Based upon Caltech RDMA design
Design improvements to improveconcentricity
Short aspect ratio to enablemeasurements to 1 nm
http://find/http://goback/8/14/2019 Flagan US China 2009
9/14
New Instrument Concepts: Opposed Migration Aerosol
Classifier
http://find/http://goback/8/14/2019 Flagan US China 2009
10/14
New Instrument Concepts: Opposed Migration Aerosol
Classifier
http://find/http://goback/8/14/2019 Flagan US China 2009
11/14
Moving detection to the single molecule level
Single molecule antibody assay
Label high-Q (108) microtoroidal
resonator
No label required on detectedmolecule or particle
Armani et al. Science (2007) 317: 783-787 (2007)
http://find/http://goback/8/14/2019 Flagan US China 2009
12/14
Moving detection to the single molecule level
http://find/http://goback/8/14/2019 Flagan US China 2009
13/14
Conclusions
Nanoparticles do have adverse health impacts when inhaled
A framework for understanding health consequences is developing
Airborne nanoparticle measurements are needed wherever engineered
nanoparticles are produced or handled
Free nanoparticles are short-lived so local measurements are needed
Identification of engineered nanoparticles remains a challengeMeasurementment methods are available and improving
Nanotechnology is opening door to single molecule and attomolardetection
Continued development is needed so that true exposure can bemonitored for those at greatest risk
Workers
General public?
http://find/http://goback/8/14/2019 Flagan US China 2009
14/14
http://find/http://goback/Top Related