| 51. |
- Sigsgaard, Torben, et al.
(författare)
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Health impacts of anthropogenic biomass burning in the developed world.
- 2015
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Ingår i: The European respiratory journal. - : European Respiratory Society (ERS). - 1399-3003 .- 0903-1936. ; 46:6, s. 1577-1588
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Tidskriftsartikel (refereegranskat)abstract
- Climate change policies have stimulated a shift towards renewable energy sources such as biomass. The economic crisis of 2008 has also increased the practice of household biomass burning as it is often cheaper than using oil, gas or electricity for heating. As a result, household biomass combustion is becoming an important source of air pollutants in the European Union.This position paper discusses the contribution of biomass combustion to pollution levels in Europe, and the emerging evidence on the adverse health effects of biomass combustion products.Epidemiological studies in the developed world have documented associations between indoor and outdoor exposure to biomass combustion products and a range of adverse health effects. A conservative estimate of the current contribution of biomass smoke to premature mortality in Europe amounts to at least 40000 deaths per year.We conclude that emissions from current biomass combustion products negatively affect respiratory and, possibly, cardiovascular health in Europe. Biomass combustion emissions, in contrast to emissions from most other sources of air pollution, are increasing. More needs to be done to further document the health effects of biomass combustion in Europe, and to reduce emissions of harmful biomass combustion products to protect public health.
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| 52. |
- Svensson, Christian, et al.
(författare)
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Characteristics of airborne gold aggregates generated by spark discharge and high temperature evaporation furnace: Mass-mobility relationship and surface area
- 2015
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Ingår i: Journal of Aerosol Science. - : Elsevier BV. - 0021-8502. ; 87, s. 38-52
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Tidskriftsartikel (refereegranskat)abstract
- The properties of gas-borne aggregates are important in nano-technology and for potential health effects. Gold aggregates from three generators (one commercial and one custom built spark discharge generator and one high-temperature furnace) have been characterized. The aggregate surface areas were determined using five approaches - based on aggregation theory and/or measured aggregate properties. The characterization included mass-mobility relationships, effective densities (assessed by an Aerosol Particles Mass analyzer), primary particle analysis (based on Transmission Electron Microscopy), as well as total mass and number concentration outputs. The relationships between mass and mobility are well described by power-law functions with exponents of 2.18-2.35. For all generators, the primary particles of the aggregates were fused together by a bridge with a diameter typically similar to 60-70% of the primary particle diameter (5-10 nm). The total mass outputs were 6.1-48.1 mg/m3 and the predicted surface area outputs in the range 0.9 x 10(-3)-17 x 10(-3) cm(2)/cm(3). The aggregate effective densities differed considerably between generators. The difference could partly be explained by the differences in primary particle diameter, but not fully. This in turn may be explained either by a varying primary particle size with aggregate size, or by that there are slight differences in the morphology of the aggregates from the generators. (C) 2015 The Authors. Published by Elsevier Ltd.
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| 53. |
- Svensson, Christian, et al.
(författare)
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Validation of an air–liquid interface toxicological set-up using Cu, Pd, and Ag well-characterized nanostructured aggregates and spheres
- 2016
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Ingår i: Journal of Nanoparticle Research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 18:4
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Systems for studying the toxicity of metal aggregates on the airways are normally not suited for evaluating the effects of individual particle characteristics. This study validates a set-up for toxicological studies of metal aggregates using an air–liquid interface approach. The set-up used a spark discharge generator capable of generating aerosol metal aggregate particles and sintered near spheres. The set-up also contained an exposure chamber, The Nano Aerosol Chamber for In Vitro Toxicity (NACIVT). The system facilitates online characterization capabilities of mass mobility, mass concentration, and number size distribution to determine the exposure. By dilution, the desired exposure level was controlled. Primary and cancerous airway cells were exposed to copper (Cu), palladium (Pd), and silver (Ag) aggregates, 50–150 nm in median diameter. The aggregates were composed of primary particles 2, respectively, were achieved. Viability was measured by WST-1 assay, cytokines (Il-6, Il-8, TNF-a, MCP) by Luminex technology. Statistically significant effects and dose response on cytokine expression were observed for SAEC cells after exposure to Cu, Pd, or Ag particles. Also, a positive dose response was observed for SAEC viability after Cu exposure. For A549 cells, statistically significant effects on viability were observed after exposure to Cu and Pd particles. The set-up produced a stable flow of aerosol particles with an exposure and dose expressed in terms of number, mass, and surface area. Exposure-related effects on the airway cellular models could be asserted. Graphical Abstract: [Figure not available: see fulltext.]
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| 54. |
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| 55. |
- Timonen, Hilkka, et al.
(författare)
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Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle
- 2017
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 17:8, s. 5311-5329
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Tidskriftsartikel (refereegranskat)abstract
- The effect of fuel ethanol content (10, 85 and 100 %) on primary emissions and on subsequent secondary aerosol formation was investigated for a Euro 5 flex-fuel gasoline vehicle. Emissions were characterized during a New European Driving Cycle (NEDC) using a comprehensive setup of high time-resolution instruments. A detailed chemical composition of the exhaust particulate matter (PM) was studied using a soot particle aerosol mass spectrometer (SPAMS), and secondary aerosol formation was studied using a potential aerosol mass (PAM) chamber. For the primary gaseous compounds, an increase in total hydrocarbon emissions and a decrease in aromatic BTEX (benzene, toluene, ethylbenzene and xylenes) compounds was observed when the amount of ethanol in the fuel increased. In regard to particles, the largest primary particulate matter concentrations and potential for secondary particle formation was measured for the E10 fuel (10% ethanol). As the ethanol content of the fuel increased, a significant decrease in the average primary particulate matter concentrations over the NEDC was found. The PM emissions were 0.45, 0.25 and 0.15 mgm-3 for E10, E85 and E100, respectively. Similarly, a clear decrease in secondary aerosol formation potential was observed with a larger contribution of ethanol in the fuel. The secondary-toprimary PM ratios were 13.4 and 1.5 for E10 and E85, respectively. For E100, a slight decrease in PM mass was observed after the PAM chamber, indicating that the PM produced by secondary aerosol formation was less than the PM lost through wall losses or the degradation of the primary organic aerosol (POA) in the chamber. For all fuel blends, the formed secondary aerosol consisted mostly of organic compounds. For E10, the contribution of organic compounds containing oxygen increased from 35 %, measured for primary organics, to 62% after the PAM chamber. For E85, the contribution of organic compounds containing oxygen increased from 42% (primary) to 57% (after the PAM chamber), whereas for E100 the amount of oxidized organics remained the same (approximately 62 %) with the PAM chamber when compared to the primary emissions.
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| 56. |
- Török, Sandra, et al.
(författare)
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Investigation of the absorption Ångström exponent and its relation to physicochemical properties for mini-CAST soot
- 2018
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Ingår i: Aerosol Science and Technology. - : Informa UK Limited. - 0278-6826 .- 1521-7388. ; 52:7, s. 757-767
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a mini-CAST soot generator was used to produce soot with different optical and physicochemical characteristics. Absorption Ångström exponents (AAE) expressing the absorption wavelength dependence were assessed by multiwavelength in-situ and filter-based (aethalometer) laser extinction. The two optical techniques showed good agreement. For the chosen mini-CAST operating conditions, AAEs between 1 and 3.5 were found. Soot with high mass-fractions of organic carbon (OC) and pyrolytic carbon (PC) determined with thermal optical analysis were associated with AAEs significantly higher than 1. Heating to 250 and 500°C removed the majority of polycyclic aromatic hydrocarbons. However, the thermal-optical analysis revealed that OC and PC were abundant in the soot with AAE > 2 also after heating the aerosol. Analysis of mass absorption cross section ratios for elemental carbon and OC indicated that elevated AAEs also after heating to 500°C could be related to persistent OC and PC components and/or the refractory soot. By comparing the mini-CAST soot optical properties with soot properties derived from in-situ extinction measurements in a premixed flame, mini-CAST soot with a higher AAE could be identified as less mature soot.
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| 57. |
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| 58. |
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