Control of solute concentrations in cloud and fog water by liquid water content

Elbert, Wolfgang; Hoffmann, Michael R.; Krämer, M.; Schmitt, G.; Andreae, Meinrat O.

doi:10.1016/s1352-2310(99)00351-9

Cited by 75 publications

(51 citation statements)

References 75 publications

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“…An inverse relationship between measured ion concentrations and liquid water content (LWC) of clouds was observed by Elbert et al (2000). In our study, the LWC in mg m -3 was calculated for each sample by the fog water collection rate (FWCR) in mg min -1 divided by the product of the fog collectors fog collection efficiency (FCE) and flow rate (FR):…”

Section: Chemical Analysismentioning

confidence: 90%

Chemical Composition of Fog Water at Four Sites in Taiwan

Šimon

Klemm

El-Madany

et al. 2016

Aerosol Air Qual. Res.

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This study characterizes and compares the chemical composition of fog water at four sites in Taiwan. Fog was sampled with identical active fog collectors (modified Caltech design) using identical sampling strategies at all four sites. While the sites varied largely in terms of altitude above mean sea level (asl), type of fog, and the potential sources of constituents in fog water, the chemical composition of fog water was in all cases clearly dominated by H + , NH 4 + , NO 3 -and SO 4 2-, making up more than 85% of the total ion concentrations. The pH ranged from 2.27 to 5.95.Sulfur dioxide emissions from coal combustion in Mainland China and Taiwan as well as nitrogen oxide emissions from urbanized central-west Taiwan and the greater Taipei region were the main precursors of fog acidity. Ammonia, originating from agriculture emissions, was the main neutralizer. The Kinmen site (48 m asl), situated on an island close to Mainland China, exhibited the lowest pH and the highest sulfate concentrations. At the Xitou site on the western slopes of the Taiwan Central Mountain Range (1150 m asl), ammonium from agriculture dominated and lead to relatively high pH. At the same time, the nitrate/sulfate ratio was highest at this site (> 1 in equivalent units), resulting from relatively large contributions from street traffic. The ion concentrations at the Chilan site (1650 m asl) and the Lulin high mountain site (2862 m asl) were much lower than those at Xitou and Kinmen. While the ion concentrations at Chilan were considerably lower than at Lulin, the ion loadings, which is the amount of dissolved ions per volume of air, were similar at Chilan and Lulin.

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Section: Chemical Analysismentioning

confidence: 90%

Chemical Composition of Fog Water at Four Sites in Taiwan

Šimon

Klemm

El-Madany

et al. 2016

Aerosol Air Qual. Res.

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“…PM 2.5 is likely to be the main source of ions in cloud water. To understand the exchange and variation of the three major ions (SO (Aleksic and Dukett, 2010;Elbert et al, 2000). As mentioned above, LWC also determined the size of cloud droplets.…”

Section: Interaction Between Aerosols and Cloud Chemical Propertiesmentioning

confidence: 99%

Chemical composition and droplet size distribution of cloud at the summit of Mount Tai, China

Li¹,

Wang²,

Chen³

et al. 2017

Atmos. Chem. Phys.

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Abstract. The chemical composition of 39 cloud samples and droplet size distributions in 24 cloud events were investigated at the summit of Mt. Tai from July to October 2014. Inorganic ions, organic acids, metals, HCHO, H 2 O 2 , sulfur(IV), organic carbon, and elemental carbon as well as pH and electrical conductivity were analyzed. The acidity of the cloud water significantly decreased from a reported value of pH 3.86 during (Guo et al., 2012 to pH 5.87 in the present study. The concentrations of nitrate and ammonium were both increased since 2007-2008, but the overcompensation of ammonium led to an increase in the mean pH value. The microphysical properties showed that cloud droplets were smaller than 26.0 µm and most were in the range of 6.0-9.0 µm at Mt. Tai. The maximum droplet number concentration (N d ) was associated with a droplet size of 7.0 µm. High liquid water content (LWC) values could facilitate the formation of larger cloud droplets and broadened the droplet size distribution. Cloud droplets exhibited a strong interaction with atmospheric aerosols. Higher PM 2.5 levels resulted in higher concentrations of water-soluble ions and smaller sizes with increased numbers of cloud droplets. The lower pH values were likely to occur at higher PM 2.5 concentrations. Clouds were an important sink for soluble materials in the atmosphere. The dilution effect of cloud water should be considered when estimating concentrations of soluble components in the cloud phase.

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“…As NH 3 is very soluble in water, its absorption have supplied some of the fog-and rainwater NH + 4 (Crutzen and Andreae, 1990). It is recognized that ion concentrations typically decrease when LWC increases (Elbert et al, 2000) due to a dilution effect. Unfortunately, no LWC measurements could be made during the period of this work.…”

Section: Chemical Composition Of Fog-and Rainwatermentioning

confidence: 99%

Fog- and Rainwater Chemistry in the Tropical Seasonal Rain Forest of Xishuangbanna, Southwest China

Liu

Meng

et al. 2005

Water Air Soil Pollut

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Abstract. Fogwater, fog drip and rainwater chemistry were examined at a tropical seasonal rain forest in Xishuangbanna, southwest China between November 2001 and October 2002. During the period of observation, 204 days with the occurrence of radiation fog were observed and the total duration of fog was 1949 h, of which 1618 h occurred in the dry season (November to April), accounting for 37.0% of the time during the season. The mean pH of fogwater, fog drip and rainwater were 6.78, 7.30, and 6.13, respectively. The ion with the highest concentration for fog-and rainwater was HCO , and K + in fogwater samples collected in the dry season were significantly greater when compared to those collected in the rainy season. It was found that the ionic concentrations in fog drip were higher than those in fogwater, except for NH + 4 and H + , which was attributed to the washout of the soil-and ash-oriented ions deposited on the leaves and the alkaline ionic emissions by the leaves, since biomass burns are very common in the region and nearby road was widening.

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Control of solute concentrations in cloud and fog water by liquid water content

Cited by 75 publications

References 75 publications

Chemical Composition of Fog Water at Four Sites in Taiwan

Chemical Composition of Fog Water at Four Sites in Taiwan

Chemical composition and droplet size distribution of cloud at the summit of Mount Tai, China

Fog- and Rainwater Chemistry in the Tropical Seasonal Rain Forest of Xishuangbanna, Southwest China

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