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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

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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.

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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.

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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

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Differential mobility analysis

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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

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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

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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

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New Instrument Concepts: Opposed Migration Aerosol

Classifier

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New Instrument Concepts: Opposed Migration Aerosol

Classifier

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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)

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Moving detection to the single molecule level

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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?

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