Challenges in Characterizing Small Particles Exploring Particles from the Nano- to Microscale: A Workshop Summary (2012) / Chapter Skim
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2 What Are Small Particles and Why Are They Important?
2 What Are Small Particles and Why Are They Important?
Pages 5-20
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In Earth's subsurface, accumulated over many years, it is known that atmospheric small particles impact soil and water quality. In living sys- nanoparticles contain a large number of polar groups, includtems, small particles impact organism health and viability.
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of For example, the haze that hangs over beaches results from solar power provided from the sun, approximately 70 percent aerosolized sea salt reflecting light. Atmospheric aerosols is absorbed (237 W/m2)
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. temperature of the climate system is to a change in the Given the increases in atmospheric CO2, CH4, N2O, and radiative forcing; it is expressed in degrees Kelvin per Watt CFC concentrations over the industrial period, and using per meter squared (K/(Wm–2)
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Figure 2-4 if the climate community is going to make the neces result, Schwartz elaborated on climate forcing by aerosols and sary advances in understanding climate sensitivity, then it graphs are uneditable raster bitmap how estimates of aerosol direct forcing are made by linear must determine the parameters that drive aerosol forcing modeling and radiation transfer modeling. These calculations arewith much greater accuracy than at present.
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chemistry. He likened that situation to regulating all airborne HEALTH IMPACTS OF AMBIENT AIR PARTICLES R02144gaseous pollutants in sum.
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It correlates Lippmann leads the National Particle Component Toxicity better with cardiovascular effects than other monitored air Initiative that aims to compile data on elemental tracers from pollutants. However, its risk coefficient varies, presumably different sources to enable source apportion analysis that resulting from differences in PM composition, and he called can be used to determine what sources generate PM mass.
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Lippmann et al., 2006. R02144 tracers associated with steel industry furnaces dominate asFigureetermined that nickel and vanadium vary "much more sig d 2-8 uneditable raster bitmap mortality than any other measured elemental the primary PM source in Birmingham, coal sources domi- nificantly with nate in western Pennsylvania, and wood burning dominates component" (Lipfert et al., 2006, Lippmann et al., 2006)
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Lippmann and his colleagues observed similarly associations for metals than for PM2.5 mass, but data on elevated levels of cardiovascular disease near the largest PM2.5 components have been too limited in frequency to Asian nickel refinery located in China, and 1,000 miles adequately support definitive time-series studies and too downwind from a nickel smelter in Ontario. Nickel smelters, limited in spatial coverage to adequately identify the effects Lippmann noted, do not emit vanadium, although they do of PM components that are not uniformly distributed.
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A complex set of minerals, asbestos is a including his, are stepping back to look more at changes in nanomaterial in Hochella's view because, even though it is a particles due to environmental influences, such as lead sullong fiber, two of its dimensions are in the nanometer range, fide and dissolution of the lead content. It is now possible to and it is these dimensions that enable it to cause pulmonary examine individual sites such as defects on surfaces as they fibrosis, lung carcinoma, and mesothelioma.
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Figure 2-11 shows a global budget of naturally Ubiquitous Nanoparticles occurring and organic nanoparticles. Still unknown is what Recently, Hochella's team obtained EPA samples taken the additional contribution -- and impact -- of manufactured from wastewater treatment plants.
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. Cryogenic light microscopy allows the location of Gerry McDermott of the University of California, San raster bitmap uneditable fluorescently tagged small particles or cellular structure inside Francisco, talked about visualizing where particles end up the cell to be identified (LeGros et al., 2009)
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The yeast cell (Figure 2-13) , and of malaria parasites and gold instrument's field of view is large enough to image one nanoparticles inside a red blood cell (Figure 2-14)
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R02144 Figure 2-13 uneditable raster bitmap FIGURE 2-14 Tomographic image of red blood cell containing malaria parasites and gold nanoparticles. Parasites were allowed to invade red blood cells containing gold particles.
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SOURCE: McDermott, 2010.R02144 Figure 2-16 uneditable raster bitmap OPEN DISCUSSION In response to a question from Pedro Alvarez of Rice University about the size distribution of natural versus manufactured nanoparticles, Hochella said, "These natural nanomaterials show the same fascinating size-dependent properties as manufactured or synthetic ones do." He added that nanoparticles with the same chemical composition and molecular structure from the two sources have similar distributions in terms of physical, chemical, electrical, and magnetic properties. However, another participant noted a key difference between natural and synthetic nanoparticles is that synthetic nanoparticles can be much more monodisperse in terms of size and shape and homogeneous in terms of chemical composition compared to naturally occurring col loidal particles.
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life-cycle impacts of synthetic nanoparticles on the envi- Lippmann responded, "There has been an effective and ronment. In fact, elaborated Hochella, that is why Virginia continuing effort to reduce the emissions of sulfur dioxide Tech and other institutions around the world are starting into the atmosphere, with the Clean Air Act leading to a sustainable nanotechnology centers.
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