B

Poster Abstracts

MEASUREMENTS OF NEUTRAL NUCLEATING MOLECULAR CLUSTERS IN THE ATMOSPHERE

J. Zhao,1 F. L. Eisele,1 J. N. Smith,1,2 M. Chen,3 J. Jiang,3 M. Titcombe,3 C. Kuang,4 and P. H. McMurry3

1Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80301

2Department of Physics and Mathematics, University of Eastern Finland, P.O. Box 70211 Kuopio, Finland

3University of Minnesota, Department of Mechanical Engineering, Minneapolis, MN 55455

4Department of Atmospheric Science, Brookhaven National Laboratory, Upton, NY 11973-5000

Atmospheric nanoparticles produced by nucleation can subsequently grow to cloud condensation nuclei (CCN) within one or two days and hence affect cloud formation, precipitation, and atmospheric radiation budgets. As an intermediate stage between molecules and nanoparticles, neutral molecular clusters are believed to play an important role in processes that lead to boundary layer nucleation. Therefore, knowledge of chemical composition, concentrations, thermodynamic properties, and evolution of neutral molecular clusters is essential to better elucidate the nucleation mechanism and to reduce the uncertainty in nucleation rates used in global climate models.

Here we present field measurements from a recently developed chemical ionization mass spectrometer (the Cluster-CIMS) designed to measure atmospheric neutral clusters (Zhao et al., 2010). The sensitivity of the Cluster-CIMS was significantly improved by using a unique conical octopole device in the first vacuum stage for transmitting and focusing ions, which was further confirmed by ion trajectory simulations using SIMION. The Cluster-CIMS was well calibrated with an electrospray coupled to a high-resolution differential mobility analyzer (ES-HDMA). The calibration showed that the Cluster-CIMS has a relatively flat sensitivity in the mass range of 190-400 amu, covering the masses of sulfuric acid clusters containing 2-4 H2SO4. The ion cluster formation in the atmospheric-pressure inlet was controlled by two processes: neutral ionization and ion-induced clustering (IIC), which can be differentiated from the time independency of the intensity ratio between the cluster and monomer ions. Two methods were employed to separate neutral clusters from the ion-induced clustering. The concentrations and distribution of the neutral nucleating clusters containing up to 4 H2SO4 are estimated from the above methods at three measurement sites (NCAR foothill laboratory, Manitou Forest Observatory, and Atlanta). Typically, the molecular cluster concentrations are well correlated with the concentrations of nanoparticles measured simultaneously during the nucleation event periods. The Cluster-CIMS was employed to measure clusters containing both sulfuric acid and amines in summer 2010 at NCAR foothill laboratory. Correlation between these clusters and nanoparticles measured by several particle counters will be presented.

Zhao, J., F. L. Eisele, M. Titcombe, C. Kuang and P. H. McMurry. 2010. Chemical ionization mass spectrometric measurements of atmospheric neutral clusters using the Cluster CIMS. Journal of Geophysical Research 115, D08205, doi:10.1029/2009JD012606.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 63
B Poster Abstracts MEASUREMENTS OF NEUTRAL NUCLEATING octopole device in the first vacuum stage for transmitting MOLECULAR CLUSTERS IN THE ATMOSPHERE and focusing ions, which was further confirmed by ion trajectory simulations using SIMION. The Cluster-CIMS J. Zhao,1 F. L. Eisele,1 J. N. Smith,1,2 M. Chen,3 J. Jiang,3 was well calibrated with an electrospray coupled to a high- M. Titcombe,3 C. Kuang,4 and P. H. McMurry3 resolution differential mobility analyzer (ES-HDMA). The 1Atmospheric Chemistry Division, National Center for calibration showed that the Cluster-CIMS has a relatively Atmospheric Research, Boulder, CO 80301 flat sensitivity in the mass range of 190-400 amu, covering 2Department of Physics and Mathematics, University of the masses of sulfuric acid clusters containing 2-4 H2SO4. Eastern Finland, P.O. Box 70211 Kuopio, Finland The ion cluster formation in the atmospheric-pressure inlet 3University of Minnesota, Department of Mechanical was controlled by two processes: neutral ionization and ion- Engineering, Minneapolis, MN 55455 induced clustering (IIC), which can be differentiated from 4 Department of Atmospheric Science, Brookhaven the time independency of the intensity ratio between the National Laboratory, Upton, NY 11973-5000 cluster and monomer ions. Two methods were employed to separate neutral clusters from the ion-induced clustering. The Atmospheric nanoparticles produced by nucleation can concentrations and distribution of the neutral nucleating clus- subsequently grow to cloud condensation nuclei (CCN) ters containing up to 4 H2SO4 are estimated from the above within one or two days and hence affect cloud formation, methods at three measurement sites (NCAR foothill labora- precipitation, and atmospheric radiation budgets. As an tory, Manitou Forest Observatory, and Atlanta). Typically, intermediate stage between molecules and nanoparticles, the molecular cluster concentrations are well correlated with neutral molecular clusters are believed to play an important the concentrations of nanoparticles measured simultaneously role in processes that lead to boundary layer nucleation. during the nucleation event periods. The Cluster-CIMS was Therefore, knowledge of chemical composition, concentra- employed to measure clusters containing both sulfuric acid tions, thermodynamic properties, and evolution of neutral and amines in summer 2010 at NCAR foothill laboratory. molecular clusters is essential to better elucidate the nucle- Correlation between these clusters and nanoparticles mea- ation mechanism and to reduce the uncertainty in nucleation sured by several particle counters will be presented. rates used in global climate models. Here we present field measurements from a recently Zhao, J., F. L. Eisele, M. Titcombe, C. Kuang and P. H. McMurry. 2010. d eveloped chemical ionization mass spectrometer (the Chemical ionization mass spectrometric measurements of atmospheric Cluster-CIMS) designed to measure atmospheric neutral neutral clusters using the Cluster CIMS. Journal of Geophysical Research 115, D08205, doi:10.1029/2009JD012606. clusters (Zhao et al., 2010). The sensitivity of the Cluster- CIMS was significantly improved by using a unique conical 63

OCR for page 63
64 APPENDIX B IN SITU STUDIES OF EQUILIBRIUM AND EXPLORING PARTICLES FROM THE NANO- TO NON-EQUILIBRIUM SMALL-PARTICLE DYNAMICS MICROSCALES ELECTRON MICROSCOPIC ANALYSES OVER EXTENDED LENGTH AND TIME SCALES USING ON ENGINEERED AND INCIDENTAL NANOPARTICLES ULTRASMALL-ANGLE X-RAY SCATTERING/X-RAY IN BIOSOLID PRODUCTS PHOTON CORRELATION SPECTROSCOPY B. Kim,1 C.-S. Park,2 M. Murayama,2,3 and M. F. Hochella, (USAXS/XPCS) Jr.1,3 J. Allen,1 F. Zhang,1 L. E. Levine,1 J. Ilavsky,2 A. R. Sandy,2 1The Center for NanoBioEarth, Department of Geosci - and G. G. Long1,2 ences, Virginia Tech, Blacksburg, VA 24061 1Material Measurement Lab., NIST, Gaithersburg, MD. 2Department of Materials Science and Engineering, Vir- Email: Andrew.allen@nist.gov ginia Tech, Blacksburg, VA 24061 2 X-ray Science Div., APS, Argonne National Lab., 3Institute for Critical Technology and Applied Science, Argonne, IL. Email: ilavsky@aps.anl.gov Virginia Tech, Blacksburg, VA 24061 Both scattering and imaging techniques successfully With the dramatic growth of nanotechnology, the pro- characterize the microstructures of advanced materials, duction and use of engineered nanoparticles has been including small particle systems and suspensions. Yet the r apidly increasing for the past few years. Engineered dynamics of these materials, especially responses to abrupt nanoparticles that are produced and/or incorporated into changes in environment, largely remain elusive. X-ray pho- consumer products will enter the environment after and/or ton correlation spectroscopy (XPCS) has emerged as a tech- during the term of use, which in turn has raised concerns nique offering unprecedented sensitivity to equilibrium and about their potentially adverse impact on the environment. nonequilibrium dynamics within material systems, including However, there has been little success with identifying nano- small particles. However, existing XPCS facilities are limited sized engineered and incidental particles from complex het- to microstructure length scales smaller than 50 nanometers, erogeneous environmental samples, limiting our understand- eliminating large classes of materials of technological impor- ing of their environmental fate and influence. Lack of such tance. Recently, we have developed combined ultrasmall- studies is in part due to technical challenges in discovering angle x-ray scattering/x-ray photon correlation spectroscopy and monitoring the environmental occurrence of engineered (USAXS/XPCS) to probe the slow equilibrium and nonequi- and incidental nanoparticles present at trace levels. In order librium dynamics of optically opaque materials with features to overcome this problem, we looked at a “bottleneck” for in a size range from 100 nm to several micrometers, i.e., engineered nanoparticles in the form of a large metropolitan between those of dynamical light scattering and conven- wastewater treatment facility. There, nanoparticles from con- tional XPCS. Two examples illustrate the in situ capability sumer products may concentrate especially at the end stage of USAXS-XPCS: the equilibrium dynamics of colloidal of treatment processes where biosolids (sludges) are gener- particle dispersions at various volume concentrations as a ated. We looked for the presence of nanosized particles in this function of temperature; and the nonequilibrium dynamics complex organic material using analytical high-resolution of the small particle configuration within a polymer com- transmission electron microscopy. We found nanoparticulate posite, for which USAXS/XPCS reveals incipient dynamical silver sulfides, presumably derived from silver nanoparticles changes not observable by other techniques. and/or ionic Ag that were reacting with reduced S species in the sedimentation processes during wastewater treatment, as well as a variety of titanium oxide nanoparticles. For both materials, their size, morphology, elemental compositions, and degree of crystallinity and aggregation state were studied in detail. The results of our work clearly show a great degree of nanoparticle heterogeneity and complexity in biosolid products. We believe that this study will help us evaluate fur- ther risks when nanoparticle-bearing biosolid products enter the soil environment through agricultural land applications.

OCR for page 63
65 APPENDIX B CHARACTERIZATION OF MICRO-PARTICLE ADHESION IMAGING SMALL PARTICLES IN CELLS USING SOFT IN PHARMACEUTICAL ENGINEERING X-RAY TOMOGRAPHY N. Zarate,1 D. Balachandran,1 J. Litster,1 and S. Beaudoin1 M. Uchida,1,3 E. Hanssen,2 C. Knoechel,1,3 G. McDermott,1,3 M. Le Gros,3,4 L. Tilley,5 and C. Larabell13,4 1School of Chemical Engineering, Purdue University, 1Department of Anatomy, University of California San West Lafayette, IN 47906 Francisco, San Francisco, CA 94143, USA 2Electron Microscopy Unit Bio21, Molecular Science The understanding of interaction forces that arise when particles and surfaces come into close contact continues to and Biotechnology Institute, University of Melbourne, Mel- be a significant focus of research. It can benefit many areas bourne, VIC 3010, Australia 3National Center for X-ray Tomography, Lawrence Berke- of study particularly in the pharmaceutical, chemical, and mineral industries involving solid processing. The work ley Laboratory, Berkeley, CA 94720, USA 4 Physical Biosciences Division, Lawrence Berkeley presented investigates capillary condensation effect on adhe- sion forces between particles and surfaces as it is exposed to National Laboratory, Berkeley, CA 94720, USA 5Department of Biochemistry and Center of Excellence different levels of relative humidity. Direct force measure- ments between molecularly smooth surfaces seem to match for Coherent X-ray Science, La Trobe University, Melbourne, accurately with conventional models, but with real particles VIC 3086, Australia and surfaces the forces display extreme discrepancies due to their natural heterogeneity such as roughness and uneven Soft x-ray tomography (SXT) is a new tool for imaging liquid condensate layers. whole, hydrated biological specimens up to 15 microns thick The investigations on the microscale interactions are with a spatial resolution better than 50 nm. In SXT, cells developed for nonideal surfaces to give more significant are imaged using photons between the K shell absorption edges of carbon (284 eV, λ = 4.4 nm) and oxygen (543 eV, insight on the macroscale than ideal surfaces. The results λ = 2.3 nm). These photons readily penetrate the aqueous have confirmed liquid condensation is present on the surface area of tooling surface on the microscale through a phase environment while encountering significant absorption from imaging technique. This was the first time it was applied carbon- and nitrogen-containing organic material. In this in the context of pharmaceutical manufacturing, which energy range, referred to as the “water window,” organic can facilitate the design of surfaces during processing. The material absorbs approximately an order of magnitude more traditional approach for designing processing and particle strongly than water, producing quantitative, high-contrast interactions heavily relied on the behavior of large amounts images of intact, fully hydrated cells without the need to of particles and indirect measurements of the adhesion forces use contrast-enhancing agents. The high penetrating power, of the surface. The understanding of the interactions between coupled with a near absence of reflection at the interface of single particles and tooling surfaces can provide useful dissimilar materials, makes x-rays an ideal probe for study- information through several characterization techniques ing cellular morphology. These unique imaging properties such as atom force microscopy (AFM) and scanning electron also make x-ray a powerful tool for determining the precise microscopy (SEM). position of small particles with respect to cellular structures.

OCR for page 63
66 APPENDIX B CHARACTERIZING MOLECULAR CONJUGATION AND CHEMICAL IMAGING ACTIVITIES ASSOCIATED WITH AGGREGATION OF NANOSCALE PARTICLES USING NANOPARTICLES AT PACIFIC NORTHWEST NATIONAL COMPLEMENTARY PHYSICAL MEASUREMENT LABORATORY METHODS S. Thevuthasan,1 L. Terminello,1 and E Hui1 Tsai,1 Cho,1 DelRio,1 MacCuspie,1 1Pacific Northwest National Laboratory, Richland, WA D.-H. T.-J. F. R. I. M. R. Zachariah,1,2 and V. A. Hackley1 99354, Theva@pnl.gov 1Materials Measurement Laboratory, National Institute of Chemical analysis and identification through direct imag- Standards and Technology, Gaithersburg, MD 20899 2Departments of Mechanical Engineering & Chemistry, ing is a powerful means to develop an atomistic understand- ing of scientific issues associated with knowledge gaps and University of Maryland, College Park, MD 20742 problems in energy, environment, and national security. We present results based on complementary physical For example, identification of mechanisms associated with c haracterization methods performed under both fluid- transformations requires the direct observation of the reac- based and aerosolized conditions in order to interrogate the tions to develop the atom-by-atom model of the structural molecular conjugation and colloidal stability of nanoscale and chemical changes. Recently we introduced a laboratory- particles. From the change in hydrodynamic and aerosol par- wide chemical imaging initiative to develop the suite of tools ticle size, we can probe the formation of molecular coatings needed for such a transformation. Central to this initiative and particle aggregates. For the purpose of characterizing will be development of an in situ tool suite with nanometer nanoscale gold-based platforms for cancer therapeutics, resolution and element specificity that will allow researchers citrate-stabilized gold nanoparticles (Au-NPs) conjugated by to couple the molecular-level chemical and structural infor- thiolated polyethylene glycol (SH-PEG) are used as a model mation to large-scale scientific challenges. In particular, we system. Dynamic light scattering and asymmetric-flow field will develop (a) synchrotron light-source-based capabilities flow fractionation are used to characterize particle popula- coupled with laboratory-based imaging capabilities for three- tions under relevant fluid conditions. For comparison, atomic dimensional tomographic, structural, and element-specific force microscopy and electrospray differential mobility interrogation at the molecular level, (b) coupled optical, analysis offer static imaging and dry aerosol characteriza- electron, ion, mass, and scanning probe microscopies to tion, respectively. Combining information derived from these understand chemical, material, and biological transforma- physical-based methods, we can then analyze the molecular tions and mechanisms, and (c) integrative hardware and soft- conformation of SH-PEG on the Au-NP surface, calculate ware applications for real-time image reconstruction, feature the surface coverage of SH-PEG, and estimate the degree extraction, and information integration. Brief descriptions of aggregation and shelf life of Au-NP based products in of these activities will be presented along with the detailed dispersed form. descriptions of two to three projects related to nanoparticle characterization.

OCR for page 63
67 APPENDIX B IMPORTANCE OF SYNERGISM IN ATMOSPHERIC HARD SHELL GAS-FILLED CONTRAST SECONDARY ORGANIC AEROSOL FORMATION: ENHANCEMENT PARTICLES FOR COLOR DOPPLER CASE STUDY OF a-PINENE OXIDATION BY NO3 ULTRASOUND IMAGING OF TUMORS RADICALS H. P. Martinez,1 Y. Kono,2 S. L. Blair,3 R. F. Mattrey,2 A. C. Perraud,1 Bruns,1 Ezell,1 Johnson,1 Kummel,1 and W. C. Trogler1 V. E. A. M. J. S. N. Y. Yu,2 M. L. Alexander,3 A. Zelenyuk,3 D. Imre,4 and B. J. 1University of California San Diego, 9500 Gilman Dr., Finlayson-Pitts1 La Jolla, CA 92093-0358; martinez@ucsd.edu,wtrogler@ 1Department of Chemistry, University of California, ucsd.edu 2University of California San Diego, Medical Center, Irvine, CA 92697 2Currently at California Air Resources Board, 9528 Tel- Dickson St., San Diego, CA 92103 3University of California San Diego, Moores Cancer star Avenue, El Monte, CA 91731 3Pacific Northwest National Laboratory, P.O. Box 999, Center, 3855 Health Sciences Dr., La Jolla, CA 92093 Richland, WA 99352 4Irme Consulting, 181 McIntosh Ct., Richland, WA 99352 Hollow hard shell particles of 200 nm and 2 micron diameter with a 10-nm-thick porous silica shell have been Secondary organic aerosols (SOAs) formed from the gas- synthesized using polystyrene templates and a sol-gel pro- phase oxidation of volatile organic compounds (VOCs) are a cess. The template insures than the hollow particles are major component of atmospheric particles. Biogenic VOCs monodispersed, while the charged silica surface insures that have been long known as SOA sources via oxidation by O3, they remain suspended in solution for weeks. When filled OH radicals, and NO3 radicals. While these reactions are with perfluorocarbon gas, the particles behave as an effi- usually studied separately in laboratory controlled experi- cient contrast agent for color Doppler ultrasound imaging in ments, in the atmosphere, reaction of VOC with one specific human breast tissue. The silica shell provides unique proper- oxidant rarely occur in isolation. We report here the oxidation ties compared to conventional soft shell particles employed of a-pinene, a well-documented biogenic emission, by NO3 as ultrasound contrast agents: uniform size control, strong radicals with varying contributions from the O3 reaction, adsorption to tissue and cells immobilizing particles at the where the O3 + NO2 reaction is the source of NO3 radicals. tissue injection site, a long imaging lifetime, and a silica Experiments were carried out in air using a newly developed surface that can be easily modified with biotargeting ligands large stainless steel flow tube. Particle concentration and or small molecules to adjust the surface charge and polarity. chemical composition were measured simultaneously using scanning mobility and aerodynamic particle sizers, two aerosol mass spectrometers, and two integrative sampling techniques (impaction on either ZnSe discs with subsequent analysis by Fourier transform infrared spectroscopy or on quartz-fiber filters followed by liquid chromatography with UV-vis detection). Even small contributions by the ozone chemistry had significant impacts on particle formation and growth, as well as on composition. The synergism between O3 and NO3 chemistry is discussed.

OCR for page 63
68 APPENDIX B CARDIOVASCULAR HEALTH EFFECTS OF PM2.5 AND EFFICIENT CHARACTERIZATION OF NANOPARTICLES NICKEL NANOPARTICLE THROUGH AN INTELLIGENT COMBINATION OF ANALYTICAL TECHNIQUES E. N. Liberda,1 A. J. Madrid,1 Q. Qu,1 and L. C. Chen1 S. V. N. T. Kuchibhatla,1 S. Thevuthasan,1 A. S. Karakoti1,2 1New York University, Department of Environmental P. Adusumilli,2 T. Prosa,3 R. Ulfig,3 V. Shutthanandan,1 Medicine, School of Medicine; eric.liberda@nyumc.org C. M. Wang,1 P. Yang,1 and S. Seal4 1EMSL, Pacific Northwest National Laboratory, Richland, It is well documented that exposure to ambient fine p articulate matter (PM2.5) creates increased risks for WA 99354 2Northwestern University, Evanston, IL 60208 cardiovascular disorders (CVD) in humans. However, the 3Cameca Instruments Inc., Madison, WI 53711 mechanism(s) and component(s) responsible for PM2.5- 4 NSTC and AMPAC, University of Central Florida, associated CVD are not known. Our recent animal studies suggest that nickel (Ni) plays critical roles in PM2.5- Orlando, FL 32826; Satya@pnl.gov associated CVD. To test this hypothesis, we identified two areas, Jinchange and Zhangye, in China with comparable “There is plenty of room at the bottom”—the visionary PM2.5 but different Ni exposures for which to investigate a statement of the legendary Feynman has been realized within variety of cardiovascular markers including reparative endo- a decade by the researchers across the globe. The advent thelial progenitor cells (EPCs). Ambient PM2.5 with high Ni of “nanoparticles” and the realization of their potential content induced elevated systemic inflammatory markers and applications in defense, energy, environment and health reduced EPCs. Additionally, we have shown that both low made the need for their synthesis and characterization quite and high concentrations of inhaled Ni nanoparticles cause essential. However, the inherently complex nature of vari- reduced numbers of bone marrow EPCs of mice as well as ous nanoparticles made their detailed characterization sig- reduced functions of these cells and may be a mechanism by nificantly intricate. Here we present two specific examples: which CVDs occur. Taken together, the results of the mouse (1) nanoparticles embedded in a matrix and (2) functional- exposure bolster the findings from the human study and point ized nanoparticles. The efforts by the team of scientists from toward a common cardiovascular maintenance cell popula- EMSL, to utilize the combination of high-resolution analyti- tion that may be adversely affected by Ni on or in PM2.5. cal electron microscopy and laser-assisted 3D-atom probe tomography for the three-dimensional chemical imaging of embedded Au-nanoparticles in MgO single crystal, will be presented. Also, in order to understand the functionalized cerium oxide (ceria) nanoparticles, we are using a com- bination of experimental, surface analysis using electron and optical spectroscopies, and theoretical analysis of the materials system. Nonlinear optical spectroscopy techniques such as SHG, SFG along with XPS, TEM, UV-Vis, and atomistic modeling are being utilized to obtain a molecular- scale visualization of the functional group conformation on the nanoparticles, surface chemistry, and its influence on the functionality of the nanoparticles.

OCR for page 63
69 APPENDIX B SIZE DISTRIBUTION MEASUREMENTS OF NEWLY NEW PARTICLE FORMATION FROM FORMED 1-6 NANOMETER ATMOSPHERIC METHANESULFONIC ACID IN AIR AEROSOLS M. L. Dawson,1 V. Perraud,1 M. J. Ezell,1 L. M. Wingen,1 Kuang,1 McMurry,2 Wang3 and B. J. Finlayson-Pitts1 C. P. and J. 1Atmospheric 1Department of Chemistry, University of California, Science Division, Brookhaven National Laboratory, Building 815E, Upton, NY 11973; ckuang@ Irvine, CA 92697-2025 bnl.gov 2Department of Mechanical Engineering, University of Identifying precursors and determining rates of formation for new particles in the atmosphere is an essential step in Minnesota, 111 Church St. SE, Minneapolis, MN 55455; quantifying the effects of particulate matter on human health mcmurry@me.umn.edu 3Atmospheric Science Division, Brookhaven National and climate change. Sulfuric acid is well known to play an important role in new particle formation, and much work has Laboratory, Building 815E, Upton, NY 11973; jian@bnl.gov been done to characterize its role as a particle precursor, with Atmospheric aerosols influence climate and climate recent studies suggesting the involvement of both ammonia change on local to global scales by affecting the atmospheric and organic amines. Methanesulfonic acid (MSA) is wide- radiation balance directly by scattering and absorbing incom- spread in the atmosphere as is formed alongside sulfuric acid ing solar radiation and indirectly as cloud condensation in the oxidation of organosulfur compounds such as dimethyl nuclei. New particle formation (NPF) by photochemical sulfide and methyl mercaptan. However much less is known reactions of gas-phase precursors greatly increases the num- about its impact on new particle formation. We report here ber concentrations of atmospheric aerosols, and therefore preliminary results from laboratory studies of new particle their impact on climate. Although methods for measuring formation and growth from the gas phase reaction of MSA sizes and concentrations N of newly formed particles of with organic amines. These studies are performed using a diameter greater than 3 nm are well established, measure- unique flow tube system equipped with an electrical aerosol ments of nanoparticles and neutral molecular clusters smaller analyzer and an scanning mobility particle sizer (SMPS), than this are needed to constrain nucleation rates and to better which are used to measure particle size distributions as a understand nucleation mechanisms. A new instrument for function of time and reactant concentration at 295 K in 1 atm “bridging the gap” in measurements from neutral molecu- of air. The implications for the role of MSA in new particle lar clusters to nanoparticles has been developed and was formation and growth will be discussed. continuously deployed in an intensive measurement cam- paign at Boulder, CO, in September 2010. Size distribution measurements down to 1 nm are achieved with an electrical mobility spectrometer using diethylene glycol as working fluid (50% activation efficiency at 1.2 nm). Under conditions of rapid NPF, N (Dp 5 nm) by more than 100 fold, greatly influencing the dynamics of the evolving aerosol.

OCR for page 63
70 APPENDIX B INHALED NICKEL NANOPARTICLES ENHANCES PHYSICOCHEMICAL PROPERTY MEASUREMENTS: PROGRESSION OF ATHEROSCLEROSIS, REDUCES KEY TO ENABLING RISK AND FATE ASSESSMENT VASCULAR REACTIVITY, AND ALTERS GENE FOR ENGINEERED NANOMATERIALS ACTIVITY IN BRAIN IN A MURINE MODEL T.-J. Cho,1 J. S. Taurozzi,1 D.-H. Tsai,1 R. I. McCuspie,1 A. J. Cuevas,1 Liberda,1 Gillespie,1 Kang,1 Allen,1 and V. A. Hackley1 A. K. E. N. P. A. G. and L.-C. Chen1 1National Institute of Standards and Technology, Nano- 1Department of Environmental Medicine, New York Uni- particle Measurements and Standards Project, Gaithersburg, versity School of Medicine, 57 Old Forge Road, Tuxedo, MD 20899 NY 10987; amj316@nyu.edu, eric.liberda@nyumc.edu, The National Institute of Standards and Technology is gillespie.patricia@gmail.com, gsk227@nyu.edu, lung-chi. actively working to address the need for physicochemical chen@nyumc.org property measurements applicable to engineered nano- There is evidence that once deposition of inhaled nano- materials (ENMs) by developing, standardizing, and vali- particles (NPs) occurs, the particles can bypass clearance dating transferable measurement methods, protocols, and mechanisms and target secondary organs, such as, the cardio- certified reference materials. Another important component vascular system and the brain. Utilizing a whole-body expo- of this effort is the interrogation of structure-property rela- sure system, ApoE-/- or C57BL/6 male mice were exposed to tionships derived from critically evaluated experimental either nickel hydroxide NPs (NHNP; 100, 150, or 900 µg/m3) results. Research activities include the following: develop- or filtered air (FA) for time periods ranging from 1 d to 5 m (5 ment of nanoscale reference materials for instrument and h/d; 5 d/w). At 24-hr post exposure, tension studies were con- method validation, laboratory qualification, and benchmark- ducted to evaluate vascular function in response to a vasocon- ing, and to support interlaboratory comparisons; studies strictors and -dilators in the carotid artery. Results indicated to develop standardized dispersion protocols for ENMs in that arteries from NHNP mice showed statistically significant biological and environmental test media, and to evaluate differences in contractile and relaxation responses compared current practices; research to assess the physicochemical to those from FA mice. Oxidative stress and inflammation in stability of nanoscale Ag and Au in biological and environ- the pulmonary and extrapulmonary system indicated dam- mental matrices; measurements to characterize and quantify age, and the degree of plaque formation was determined in the amount, conformation, and distribution of surface-bound the ascending aorta. In addition, three brain regions were molecular species; evaluation of methods for detection and collected (olfactory bulb, midbrain, and cerebellum) for characterization of aggregates formed in ENM dispersions; gene expression analyses. These results suggest that both and application of synchrotron X-ray and neutron scatter- short- and long-term exposure to inhaled NHNPs can induce ing methods to study ENM formation, interactions, and oxidative stress and inflammation in both pulmonary and functionalization. extrapulmonary organs that can accelerate atherosclerosis in ApoE-/- mice as well as alter vascular function and brain gene expression in C57BL/6 mice.

OCR for page 63
71 APPENDIX B USING MASS SPECTROMETRY TO CHARACTERIZE CHARACTERIZATION OF HIDDEN NANOPARTICLES- AIRBORNE PARTICLES POLYMER INTERFACE IN COMPOSITES E. A. Bruns,1 V. Perraud,1 M. L. Alexander,2 A. Zelenyuk,2 M. Zhao,1 B. Ming,1 A. E. Vladar,1 X. Gu,1 and T. Nguyen1 M. J. Ezell,1 S. N. Johnson,1 J. Greaves,1 D. Imre,3 and B. J. 1National Institute of Standards and Technology, Gaith - Finlayson-Pitts1 ersburg, MD 20899, mzhao@nist.gov 1Department of Chemistry, University of California, The interface of nanoparticles-polymer plays an important Irvine, CA 92697-2025 2Environmental Molecular Sciences Laboratory, Pacific role in properties and applications of nanocomposites. How- ever, few analytical techniques are suitable for characterizing Northwest National Laboratory, Richland, WA 99352 3Imre Consulting, Richland, WA 99352 this interface due to its small length scale and hidden natures. In this work, the hidden nanoparticles-polymer interface in Airborne particles affect health, reduce visibility, and composites is studied by scanning probe microscopy (SPM) impact climate by scattering light and altering cloud proper- and scanning electron microscopy (SEM). Specifically, elec- ties, and complete particle characterization is essential to tric force microscopy (EFM), a special type of SPM based understand these impacts. Secondary organic aerosols (SOAs) on long-range electrostatic interactions, and poly-transparent are a significant constituent of atmospheric particles and are SEM (PT-SEM), a newly developed SEM technique for formed from the condensation of semi-volatile oxidation subsurface imaging, were applied in this study. The high- products. The partitioning of these semi-volatile compounds resolution imaging of nanoparticles-polymer interface such between the gas phase and particles makes characterization as zinc oxide-polyurethane, titanium oxide-epoxy, carbon particularly challenging. Traditional analysis techniques nanotube-epoxy, and carbon nanotube-polyimide was dem- involve filter-based sampling and extraction, which can onstrated. The effect of experimental parameters of EFM introduce artifacts. In the past decade, real-time particle and PT-SEM on interface imaging was also discussed. In mass spectrometry has emerged as a powerful technique that particular, EFM and PT-SEM are nondestructive techniques overcomes these artifacts. However, their response to organic for the nanoscale characterization of hidden interface in both nitrates, which are present in SOAs, is unknown. Ambient thin film and bulk samples without any sample prepara- ionization mass spectrometry has also emerged as a promising tions. Hence, EFM and PT-SEM will be powerful tools not technique for particulate analysis because little or no sample only for the characterization of hidden interface in nano- preparation is needed and Fourier transform infrared (FTIR) composites, but also for a broad range of other nanotech- spectra of the same sample can be obtained. We report here nology applications. results from the analysis of laboratory-generated SOAs from the oxidation of several terpenes, including a-pinene, using high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS), atmospheric solids analysis probe mass spectrometry (ASAP-MS), and FTIR. The ability of HR- ToF-AMS, a real-time technique, to analyze organic nitrates will be explored, as will the applicability of ASAP-MS, an ambient ionization technique, to particulate analysis.

OCR for page 63