| 161. |
- Nilsson, Patrik, et al.
(författare)
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Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments
- 2013
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Ingår i: Journal of Nanoparticle Research. - : Springer Science and Business Media LLC. - 1572-896X .- 1388-0764. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Nanotechnology gives us materials with enhanced or completely new properties. At the same time, inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry (AMS), for time-and size-resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02-10 mu m, were dominated by large agglomerates (1-5 mu m). With AMS, we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time-resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (10(3)-10(5)/agglomerate) of nanometer-sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer-sized particles in exposure and emission assessments.
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| 162. |
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| 163. |
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| 164. |
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| 165. |
- Nordin, Erik, et al.
(författare)
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Influence of ozone initiated processing on the toxicity of aerosol particles from small scale wood combustion
- 2015
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 102, s. 282-289
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Tidskriftsartikel (refereegranskat)abstract
- Black carbon containing emissions from biomass combustion are being transformed in the atmosphere upon processing induced by tropospheric ozone and UV. The knowledge today is very limited on how atmospheric processing affects the toxicological properties of the emissions. The aim of this study was to investigate the influence of ozone initiated (dark) atmospheric processing on the physicochemical and toxicological properties of particulate emissions from wood combustion. Emissions from a conventional wood stove operated at two combustion conditions (nominal and hot air starved) were diluted and transferred to a chamber. Particulate matter (PM) was collected before and after ozone addition to the chamber using an impactor. Detailed chemical and physical characterization was performed on chamber air and collected PM. The collected PM was investigated toxicologically in vitro with a mouse macrophage model, endpoints included: cell cycle analysis, viability, inflammation and genotoxicity. The results suggest that changes in the organic fraction, including polycyclic aromatic hydrocarbons (PAHs) are the main driver for differences in obtained toxicological effects. Fresh hot air starved emissions containing a higher organic and PAH mass-fraction affected cell viability stronger than fresh emissions from nominal combustion. The PAH mass fractions decreased upon aging due to chemical degradation. Dark aging increased genotoxicity, reduced viability and reduced release of inflammatory markers. These differences were statistically significant for single doses and typically less pronounced. We hypothesize that the alterations in toxicity upon simulated dark aging in the atmosphere may be caused by reaction products that form when PAHs and other organic compounds react with ozone and nitrate radicals. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).
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| 166. |
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