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Aqueous phase sulfate production in ...

Shen, Xinhua.

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Aqueous phase sulfate production in clouds at Mt. Tai in eastern China.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Aqueous phase sulfate production in clouds at Mt. Tai in eastern China./
作者:	Shen, Xinhua.
面頁冊數:	193 p.
附註:	Source: Dissertation Abstracts International, Volume: 72-08, Section: B, page: .
Contained By:	Dissertation Abstracts International72-08B.
標題:	Atmospheric Chemistry. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3454634
ISBN:	9781124644714

Aqueous phase sulfate production in clouds at Mt. Tai in eastern China.
Shen, Xinhua.

Aqueous phase sulfate production in clouds at Mt. Tai in eastern China. - 193 p.

Source: Dissertation Abstracts International, Volume: 72-08, Section: B, page: .

Thesis (Ph.D.)--Colorado State University, 2011.

Clouds play an important role in the oxidation of sulfur dioxide to sulfate, since aqueous phase sulfur dioxide oxidation is typically much faster than oxidation in the gas phase. Important aqueous phase oxidants include hydrogen peroxide, ozone and oxygen (catalyzed by trace metals). Because quantities of emitted sulfur dioxide in China are so large, however, it is possible that they exceed the capacity of regional clouds for sulfate production, leading to enhanced long-range transport of emitted SO2 and its oxidation product, sulfate.

ISBN: 9781124644714Subjects--Topical Terms:

1669583
Atmospheric Chemistry.

Aqueous phase sulfate production in clouds at Mt. Tai in eastern China.
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100 1 $a Shen, Xinhua. $3 1677445
245 1 0 $a Aqueous phase sulfate production in clouds at Mt. Tai in eastern China.
300 $a 193 p.
500 $a Source: Dissertation Abstracts International, Volume: 72-08, Section: B, page: .
500 $a Adviser: Jeffrey L. Collett.
502 $a Thesis (Ph.D.)--Colorado State University, 2011.
520 $a Clouds play an important role in the oxidation of sulfur dioxide to sulfate, since aqueous phase sulfur dioxide oxidation is typically much faster than oxidation in the gas phase. Important aqueous phase oxidants include hydrogen peroxide, ozone and oxygen (catalyzed by trace metals). Because quantities of emitted sulfur dioxide in China are so large, however, it is possible that they exceed the capacity of regional clouds for sulfate production, leading to enhanced long-range transport of emitted SO2 and its oxidation product, sulfate.
520 $a In order to assess the ability of regional clouds to support aqueous sulfur oxidation, four field campaigns were conducted in 2007 and 2008 at Mt. Tai in eastern China. Single and 2-stage Caltech Active Strand Cloudwater Collectors were used to collect bulk and drop size-resolved cloudwater samples, respectively. Key species that determine aqueous phase sulfur oxidation were analyzed, including cloudwater pH, S(IV), H2O2, Fe, and Mn. Gas phase SO2, O3, and H2O2 were also measured continuously during the campaigns. Other species in cloudwater, including inorganic ions, total organic carbon (TOC), formaldehyde, and organic acids were also analyzed to provide a fuller view of cloud chemistry in the region.
520 $a Numerous periods of cloud interception/fog occurred during the four Mt. Tai field campaigns; more than 500 cloudwater samples were collected in total. A wide range of cloud pH values was observed, from 2.6 to 7.6. SO4 2-, NO3-, and NH4+ were the major inorganic species for all four campaigns. TOC concentrations were also very high in some samples (up to 200 ppmC), especially when clouds were impacted by emissions from agricultural biomass burning. Back-trajectory analysis also indicated influence by dust transport from northern China in a few spring cloud events. Differences between the compositions of small and large cloud droplets were observed, but generally found to be modest for major solute species and pH. Mt. Tai clouds were found to interact strongly with PM2.5 sulfate, nitrate, and ammonium with average scavenging efficiencies of 80%, 75%, and 78%, respectively, across 7 events studied. Scavenging efficiencies for total sulfur (PM2.5 sulfate plus gaseous sulfur dioxide), however, averaged only 43%, indicating the majority of gaseous sulfur dioxide remained unprocessed in these cloud events.
520 $a H2O2 was found to be the most important oxidant for aqueous sulfate production 68% of the time. High concentrations of residual H2O2 were measured in some samples, especially during summertime, implying a substantial capacity for additional sulfur oxidation. The importance of ozone as a S(IV) oxidant increased substantially as cloud pH climbed above pH 5 to 5.3. Overall, ozone was found to be the most important aqueous S(IV) oxidant in 21% of the sampling periods. Trace metal-catalyzed S(IV) autooxidation was determined to be the fastest aqueous sulfate production pathway in the remaining 11% of the cases. Complexation with formaldehyde was also found to be a potentially important fate for aqueous S(IV) and should be examined in more detail in future studies. Observed chemical heterogeneity among cloud drop populations was predicted to enhance rates of S(IV) oxidation by ozone and enhance or slow metal-catalyzed S(IV) autooxidation rates in some periods. These effects were found to be only of minor importance, however, as H2O2 was the dominant S(IV) oxidant most of the time.
590 $a School code: 0053.
650 4 $a Atmospheric Chemistry. $3 1669583
650 4 $a Atmospheric Sciences. $3 1019179
690 $a 0371
690 $a 0725
710 2 $a Colorado State University. $b Atmospheric Science. $3 1677446
773 0 $t Dissertation Abstracts International $g 72-08B.
790 1 0 $a Collett, Jeffrey L., $e advisor
790 1 0 $a Kreidenweis, Sonia M. $e committee member
790 1 0 $a Rutledge, Steven A. $e committee member
790 1 0 $a Reynolds, Stephen J. $e committee member
790 $a 0053
791 $a Ph.D.
792 $a 2011
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3454634