Measurements of Trace Metal (Fe, Cu, Mn, Cr) Oxidation States in Fog and Stratus Clouds

Siefert, Ronald L.; Johansen, Anne M.; Hoffmann, Michael R.; Pehkonen, Simo O.

doi:10.1080/10473289.1998.10463659

Cited by 73 publications

(97 citation statements)

References 64 publications

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“…Deutsch et al [57] evaluated the Fe(II)/Fe(III) partition in cloud water samples during two field campaigns on the top of the Kleiner Feldberg, Germany, and also found a correlation between the concentration of Fe(II) in the liquid phase and the sunlight intensity for most of the samples ( Figure 5.7). To investigate the iron chemistry in aqueous-phase measurements of iron oxidation states in fog and cloud water, samples have been combined with a kinetic model [4]. Results, which predicted that Fe(II) would be the predominant oxidation state during daylight and Fe(III) during nighttime conditions, were in agreement with field measurements.…”

Section: Redox Speciationsupporting

confidence: 60%

“…HO 2 /O − 2 , Cu(I) and S(IV)) and complexing agents (e.g. organic ligands) [4,50,[52][53][54][55][56]. Behra and Sigg [50] found that a large fraction (20-90%) of dissolved iron in fog water was present as Fe(II), which increased with exposure to light as well as with decreasing pH.…”

Section: Redox Speciationmentioning

confidence: 99%

“…), which have several oxidation states, and thus can participate in many important atmospheric redox reactions. Field measurements provide strong evidence that TM are common components in aerosol particles as well as in atmospheric liquid water [1][2][3][4][5].The concentrations of trace metals in atmospheric aerosols are a function of their sources. Natural emissions of trace metals result from different processes acting on crustal minerals (e.g.…”

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confidence: 99%

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Metals in Aerosols

Grgić

2008

Environmental Chemistry of Aerosols

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Atmospheric aerosols have important role in the biogeochemistry and transportation of metals in the atmosphere. On a mass basis, so-called trace metals represent a relatively small proportion of the atmospheric aerosol (generally less than 1%). Among them are transition metals (TM) (e.g. vanadium, chromium, manganese, iron, cobalt, nickel, copper, etc.), which have several oxidation states, and thus can participate in many important atmospheric redox reactions. Field measurements provide strong evidence that TM are common components in aerosol particles as well as in atmospheric liquid water [1][2][3][4][5].The concentrations of trace metals in atmospheric aerosols are a function of their sources. Natural emissions of trace metals result from different processes acting on crustal minerals (e.g. erosion, surface winds and volcanic eruptions), as well as from natural burning and from the oceans. On a global scale, resuspended surface dusts make a large contribution to the total natural emission of trace metals to the atmosphere (e.g. more than 50% of Cr, Mn and V, and more than 20% of Cu, Mo, Ni, Pb, Sb and Zn), whereas volcanism presumably generates about 20% of Cd, Hg, As, Cr, Cu, Ni, Pb and Sb [6]. Sea-salt aerosols generated by spray and wave action may contribute to about 10% of total trace metals emissions. Biomass combustion can contribute to emissions of Cu, Pb and Zn [7]. The predominant anthropogenic sources are due to high-temperature processes, biomass burning, fossil-fuel combustion, industrial activity, incineration, etc. Anthropogenic high-temperature processes result in the release of volatile metals as vapours forming particles by condensation or gas-to-particle reactions. Combustion of fossil fuels is the most important anthropogenic source of atmospheric Be, Co, Hg, Mo, Ni, Sb, Se, Sn and V; it also contributes to emissions of As, Cr, Cu, Mn and Zn [6]. Industrial metallurgical processes produce the largest emissions of As, Cd, Cu, Ni and Zn. Exhaust emissions from gasoline-and diesel-fuelled vehicles contribute to atmospheric Pb, Fe, Cu, Zn, Ni and Cd, while tyre-rubber abrasion to Zn [8]. In the last decade, the use of new automobile catalytic converters also contributes to the emissions of Pt, Pd and Rh [9, 10]. The composition of aerosols depends on the occurrence of metals in combustion processes and their volatility as well as on their amount produced by decomposition of continental and oceanic surfaces. Thus, the size distributions of different metals depend on the balance of different sources.Environmental Chemistry of Aerosols Edited by Ian Colbeck

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Section: Redox Speciationsupporting

confidence: 60%

Section: Redox Speciationmentioning

confidence: 99%

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confidence: 99%

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Metals in Aerosols

Grgić

2008

Environmental Chemistry of Aerosols

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“…The soluble fraction of iron over the ocean ranges from 0 to 95 % as the bulk marine aerosol type reflects a mixing of multiple aerosol types, and solubility varies with the origin of the iron, aerosol size and composition. [87][88][89] Moreover, the solubility increases owing to the photoreduction of Fe III , which is responsible for an Fe II fraction in the aerosol of up to 50 % in remote marine areas. [90] An additional crucial factor for the role of Fe III photochemistry is the aerosol pH, which varies from 1-9, mainly depending on the origin and age of the aerosol and the corresponding altering processes.…”

Section: Environmental Significancementioning

confidence: 99%

Iron(III)-induced activation of chloride from artificial sea-salt aerosol

et al. 2015

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Environmental context. Inorganic, natural aerosols (sea-salt, mineral dust, glacial flour) and contributions of anthropogenic components (fly ash, dust from steel production and processing, etc.) contain iron that can be dissolved as Fe III in saline media. This study investigates photochemical processes in clouds and aerosols producing gas-phase Cl as a function of salt-and gas-phase composition employing a simulation chamber. Atomic Cl may contribute to the oxidative capacity of the troposphere, and our findings imply local sources.Abstract. Artificial sea-salt aerosol, containing Fe III at various compositions, was investigated in a simulation chamber (made of Teflon) for the influence of pH and of the tropospheric trace gases NO 2 , O 3 and SO 2 on the photochemical activation of chloride. Atomic chlorine (Cl) was detected in the gas phase and quantified by the radical clock technique. Dilute brines with known Fe III content were nebulised until the relative humidity reached 70-90 %. The resulting droplets (most abundant particle diameter: 0.35-0.46 mm, initial surface area: up to 3 Â 10 À2 cm 2 cm À3) were irradiated with simulated sunlight, and the consumption of a test mixture of hydrocarbons was evaluated for Cl, Br and OH. The initial rate of atomic Cl production per aerosol surface increased with Fe III and was ,1. . The observed production of atomic Cl is discussed with respect to pH and speciation of the photolabile aqueous Fe III complexes.

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“…After sampling, the filters were immediately stored in sterile flasks under refrigeration until laboratory analysis. Each flask contained nitric acid solution (refiltered HNO 3 , 99.5 %) at pH 2.2 ± 0.3, in order to quench the equilibrium process between the two iron oxidative states, Fe(II) and Fe(III), and to stabilize the iron concentrations (Siefert, 1998;Bruno et al, 2000;Cwiertny et al, 2008;Trapp et al, 2010).…”

Section: Aerosol Samplingmentioning

confidence: 99%

Soluble iron nutrients in Saharan dust over the central Amazon rainforest

et al. 2017

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The intercontinental transport of aerosols from the Sahara desert plays a significant role in nutrient cycles in the Amazon rainforest, since it carries many types of minerals to these otherwise low-fertility lands. Iron is one of the micronutrients essential for plant growth, and its long-range transport might be an important source for the iron-limited Amazon rainforest. This study assesses the bioavailability of iron Fe(II) and Fe(III) in the particulate matter over the Amazon forest, which was transported from the Sahara desert (for the sake of our discussion, this term also includes the Sahel region). The sampling campaign was carried out above and below the forest canopy at the ATTO site (Amazon Tall Tower Observatory), a near-pristine area in the central Amazon Basin, from March to April 2015. Measurements reached peak concentrations for soluble Fe(III) (48 ng m−3), Fe(II) (16 ng m−3), Na (470 ng m−3), Ca (194 ng m−3), K (65 ng m−3), and Mg (89 ng m−3) during a time period of dust transport from the Sahara, as confirmed by ground-based and satellite remote sensing data and air mass backward trajectories. Dust sampled above the Amazon canopy included primary biological aerosols and other coarse particles up to 12 µm in diameter. Atmospheric transport of weathered Saharan dust, followed by surface deposition, resulted in substantial iron bioavailability across the rainforest canopy. The seasonal deposition of dust, rich in soluble iron, and other minerals is likely to assist both bacteria and fungi within the topsoil and on canopy surfaces, and especially benefit highly bioabsorbent species. In this scenario, Saharan dust can provide essential macronutrients and micronutrients to plant roots, and also directly to plant leaves. The influence of this input on the ecology of the forest canopy and topsoil is discussed, and we argue that this influence would likely be different from that of nutrients from the weathered Amazon bedrock, which otherwise provides the main source of soluble mineral nutrients

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Measurements of Trace Metal (Fe, Cu, Mn, Cr) Oxidation States in Fog and Stratus Clouds

Cited by 73 publications

References 64 publications

Metals in Aerosols

Metals in Aerosols

Iron(III)-induced activation of chloride from artificial sea-salt aerosol

Soluble iron nutrients in Saharan dust over the central Amazon rainforest

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