scholarly journals Long-range atmospheric transport of volatile monocarboxylic acids with Asian dust over a high mountain snow site, central Japan

2016 ◽  
Vol 16 (22) ◽  
pp. 14621-14633 ◽  
Author(s):  
Tomoki Mochizuki ◽  
Kimitaka Kawamura ◽  
Kazuma Aoki ◽  
Nobuo Sugimoto

Abstract. To understand the long-range transport of monocarboxylic acids from the Asian continent to the Japanese islands, we collected snowpack samples from a pit sequence (depth ca. 6 m) at the Murodo-Daira snowfield near the summit of Mt. Tateyama, central Japan, in 2009 and 2011. Snow samples (n = 16) were analyzed for normal (C1–C10), branched chain (iC4–iC6), aromatic (benzoic and toluic acid isomers), and hydroxyl (glycolic and lactic) monocarboxylic acids, together with inorganic ions and dissolved organic carbon (DOC). Acetic acid (C2) was found to be a dominant species (average 125 ng g−1), followed by formic acid (C1) (85.7 ng g−1) and isopentanoic acid (iC5) (20.0 ng g−1). We found a strong correlation (r =  0.88) between formic plus acetic acids and non-sea-salt Ca2+ that is a proxy of Asian dust. Contributions of total monocarboxylic acids to DOC in 2009 (21.2 ± 11.6 %) were higher than that in 2011 (3.75 ± 2.62 %), being consistent with higher intensity of Asian dust in 2009 than in 2011. Formic plus acetic acids also showed a positive correlation (r =  0.90) with benzoic acid that is a tracer of automobile exhaust, indicating that monocarboxylic acids and their precursors are largely emitted from anthropogenic sources in China and/or secondarily produced in the atmosphere by photochemical processing. In addition, the ratio of formic plus acetic acids to nss–Ca2+ (0.27) was significantly higher than those (0.00036–0.0018) obtained for reference dust materials of Chinese loess deposits from the Tengger and Gobi deserts. This result suggests that volatile and semi-volatile organic acids are adsorbed on the alkaline dust particles during long-range atmospheric transport. Entrainment of organic acids by dusts is supported by a good correlation (r = 0.87) between formic plus acetic acids and pH of melt snow samples. Our study suggests that Asian alkaline dusts may be a carrier of volatile monocarboxylic acids.

2016 ◽  
Author(s):  
Tomoki Mochizuki ◽  
Kimitaka Kawamura ◽  
Kazuma Aoki ◽  
Nobuo Sugimoto

Abstract. To understand the long-range transport of monocarboxylic acids from the Asian Continent to Japanese Islands, we collected snowpack samples from a pit sequence (depth, ca. 6 m) at the Murodo-Daira snowfield near the summit of Mt. Tateyama, central Japan in 2009 and 2011. Snow samples (n = 16) were analyzed for normal (C1–C10), branched chain (iC4–iC6), aromatic (benzoic and toluic acid isomers), and hydroxyl (glycolic and lactic) monocarboxylic acids, together with inorganic ions and dissolved organic carbon (DOC). Acetic acid (C2) was found as a dominant species (average, 125 ng g−1), followed by formic acid (C1) (85.7 ng g−1) and isopentanoic acid (iC5) (20.0 ng g−1). We found a strong correlation (r2 = 0.73) between formic plus acetic acids and non-sea-salt Ca2+ that is a proxy of Asian dust. Contributions of total monocarboxylic acids to DOC in 2009 (21.2 ± 11.6 %) were higher than that in 2011 (3.75 ± 2.62 %), being consistent with higher intensity of Asian dust in 2009 than 2011. Formic plus acetic acids also showed a positive correlation (r2 = 0.81) with benzoic acid that is a tracer of automobile exhaust, indicating that monocarboxylic acids and their precursors are largely emitted from anthropogenic sources in China and/or secondarily produced in the atmosphere by photochemical processing. In addition, the ratio of formic plus acetic acids to nss-Ca2+ (0.27) was significantly higher than those (0.00036–0.0018) obtained for reference dust materials of Chinese loess deposits from Tengger and Gobi deserts. This result suggests that volatile and semi-volatile organic acids are adsorbed on the alkaline dust particles during long-range atmospheric transport. Entrainment of organic acids by dusts is supported by a good correlation (r2=0.76) between formic plus acetic acids and pH of melt snow samples. Our study demonstrates that Asian alkaline dusts can uptake volatile monocarboxylic acids during long-range transport and the dusts coated with organic acids may act as effective ice nuclei to cause a heavy snowfall.


2018 ◽  
Author(s):  
Teruya Maki ◽  
Shogo Furumoto ◽  
Yuya Asahi ◽  
Kevin C. Lee ◽  
Koichi Watanabe ◽  
...  

Abstract. The westerly wind travelling at high altitudes over East Asia transports aerosols from the Asian deserts and urban areas to downwind areas such as Japan. These long-range transported aerosols include not only mineral particles, but also microbial particles (bioaerosols), that impact the ice-cloud formation processes as ice nuclei. However, the the detailed relations of airborne bacterial dynamics to ice nucleation in high-elevation aerosols have not been investigated. Here, we used the aerosol particles captured in the snow cover at the altitudes of 2450 m on Mt. Tateyama to investigate the sequential changes of ice-nucleation activities and bacterial communities in aerosols and elucidate the relationships between the two processes. After stratification of the snow layers formed on the walls of a snow pit on Mt. Tateyama, snow samples, including aerosol particles, were collected from 70 layers at the lower (winter accumulation) and upper (spring accumulation) parts of the snow wall. The aerosols recorded in the lower parts mainly came from Siberia (Russia), North Asia, and the Sea of Japan, while those in the upper parts showed an increase the Asian-dust particles, which originate from the desert regions and industrial coasts of Asian. The snow samples exhibited high levels of ice nucleation corresponding to the increase of Asian dust particles. Amplicon sequencing analysis using 16S rRNA genes revealed that the bacterial communities in the snow samples predominately included plant associated and marine bacteria (phyla Proteobacteria) during winter; whereas, during spring, when dust events arrived frequently, the majority were terrestrial bacteria of phyla Actinobacteria and Firmicutes. The relative abundances of Firmicutes (Bacilli) showed a significant positive relationship to the ice nucleation in snow samples. Presumably, Asian dust events change the airborne bacterial communities over Mt. Tateyama and carry terrestrial bacterial populations, which possibly induce ice-nucleation activities, thereby indirectly effecting on climate changes.


2018 ◽  
Vol 18 (11) ◽  
pp. 8155-8171 ◽  
Author(s):  
Teruya Maki ◽  
Shogo Furumoto ◽  
Yuya Asahi ◽  
Kevin C. Lee ◽  
Koichi Watanabe ◽  
...  

Abstract. The westerly wind travelling at high altitudes over eastern Asia transports aerosols from the Asian deserts and urban areas to downwind areas such as Japan. These long-range-transported aerosols include not only mineral particles but also microbial particles (bioaerosols), that impact the ice-cloud formation processes as ice nuclei. However, the detailed relations of airborne bacterial dynamics to ice nucleation in high-elevation aerosols have not been investigated. Here, we used the aerosol particles captured in the snow cover at altitudes of 2450 m on Mt Tateyama to investigate sequential changes in the ice-nucleation activities and bacterial communities in aerosols and elucidate the relationships between the two processes. After stratification of the snow layers formed on the walls of a snow pit on Mt Tateyama, snow samples, including aerosol particles, were collected from 70 layers at the lower (winter accumulation) and upper (spring accumulation) parts of the snow wall. The aerosols recorded in the lower parts mainly came from Siberia (Russia), northern Asia and the Sea of Japan, whereas those in the upper parts showed an increase in Asian dust particles originating from the desert regions and industrial coasts of Asia. The snow samples exhibited high levels of ice nucleation corresponding to the increase in Asian dust particles. Amplicon sequencing analysis using 16S rRNA genes revealed that the bacterial communities in the snow samples predominately included plant associated and marine bacteria (phyla Proteobacteria) during winter, whereas during spring, when dust events arrived frequently, the majority were terrestrial bacteria of phyla Actinobacteria and Firmicutes. The relative abundances of Firmicutes (Bacilli) showed a significant positive relationship with the ice nucleation in snow samples. Presumably, Asian dust events change the airborne bacterial communities over Mt Tateyama and carry terrestrial bacterial populations, which possibly induce ice-nucleation activities, thereby indirectly impacting climate change.


1983 ◽  
Vol 20 (1) ◽  
pp. 23-36 ◽  
Author(s):  
M. Ouellet ◽  
H. G. Jones

The present study deals with the geochemical stratigraphic evolution of the recent sediments of 26 lakes located throughout the Province of Quebec, Canada. Although there is no major anthropogenic activity within the watersheds of many of these lakes, it is shown that Pb, Zn, Hg, and Cu levels in the most recent sediments of all lakes increased significantly from 1940 onwards. It is suggested that these increases are due to the increased burning of fossil fuels (particularly coal). The heavy-metal increases tend to be relatively high, especially for Pb, Hg, and Zn, in the sediments of lakes from areas close to the U.S.A.–Quebec boundary, while lakes in more remote areas show smaller increases in the strata laid down in the same time periods. Pb contents in the sediments show a sustained increase in all of the upper strata. However, the subsequent reduction in the stratigraphic concentration of Zn and Hg since 1960 in both an acidified system (Lake Tantare) and a non-acidified lake (Lake Laflamme) might be the result of the important decrease of the total particulate emissions to the atmosphere associated with new technology for coal-fired power plants and the use of cleaner energy sources.The increase in Al in the sediments of Lake Tantare since 1950 is attributed to the processes of surface water acidification of this watershed induced by the long-range atmospheric transport of SOx and NOx.Based on the sedimentary anthropogenic enrichment factor (SAEF) values for the remote sites there is no evidence in the present study for associating the origin of certain heavy metals in these lake sediments with alternative anthropogenic sources such as the Ni and Cu smelting complexes located in Sudbury (Ontario) and Rouyn–Noranda (Quebec). The major sources of heavy-metal deposition and acid precipitation are thus associated with the long-range transport of emissions from fossil fuel combustion originating in the heavily industrialized American Midwest region.


2014 ◽  
Vol 14 (1) ◽  
pp. 505-521 ◽  
Author(s):  
G. Y. Jeong ◽  
J. Y. Kim ◽  
J. Seo ◽  
G. M. Kim ◽  
H. C. Jin ◽  
...  

Abstract. Giant particles transported over long distances are generally of limited concern in atmospheric studies due to their low number concentrations in mineral dust and possible local origin. However, they can play an important role in regional circulation of earth materials due to their enormous volume concentration. Asian dust laden with giant particles was observed in Korea on 31 March 2012, after a migration of about 2000 km across the Yellow Sea from the Gobi Desert. Scanning electron microscopy (SEM) revealed that 20% of the particles exceeded 10 μm in equivalent sphere diameter, with a maximum of 60 μm. The median diameter from the number distribution was 5.7 μm, which was larger than the diameters recorded of 2.5 and 2.9 μm in Asian dust storms in 2010 and 2011, respectively, and was consistent with independent optical particle counter data. Giant particles (>10 μm) contributed about 89% of the volume of the dust in the 2012 storm. Illite–smectite series clay minerals were the major mineral group followed by quartz, plagioclase, K-feldspar, and calcite. The total phyllosilicate content was ~52%. The direct long-range transport of giant particles was confirmed by calcite nanofibers closely associated with clays in a submicron scale identified by high-resolution SEM and transmission electron microscopy. Since giant particles consisted of clay agglomerates and clay-coated quartz, feldspars, and micas, the mineral composition varied little throughout the fine (<5 μm), coarse (5–10 μm), giant-S (10–20 μm), and giant-L (>20 μm) size bins. Analysis of the synoptic conditions of the 2012 dust event and its migration indicated that the mid-tropospheric strong wind belt directly stretching to Korea induced rapid transport of the dust, delivering giant particles. Giant dust particles with high settling velocity would be the major input into the terrestrial and marine sedimentary and ecological systems of East Asia and the western Pacific. Analysis of ancient aeolian deposits in Korea suggested the common deposition of giant particles from Asian dust through the late Quaternary Period. The roles of giant particles should be reviewed with regard to regional circulation of mineral particles and nutrients.


2021 ◽  
Vol 8 ◽  
Author(s):  
Krystyna Koziol ◽  
Aleksander Uszczyk ◽  
Filip Pawlak ◽  
Marcin Frankowski ◽  
Żaneta Polkowska

Metals and metalloids in snow on glaciers, depending on the season of deposition, may come from various sources: local rock dust (erosion of the geological substratum), marine aerosol, local human activity (e.g., impurities in combusted fuel and waste incineration), and long-range atmospheric transport. Hansbreen, a glacier located close to the Polish Polar Station in southern Svalbard, is a perfect site to study metals and metalloids: it has a complex geological substratum, has a year-round presence of a small group of people, and is near the coast. We analyzed a snapshot of metal and metalloid concentrations in snow samples from shallow cores corresponding to autumn, winter, and spring deposition on Hansbreen. Eighteen cores of snow were collected across the glacier, revealing the influence of potential local sources of metals and metalloids. In these samples, we predominantly found Na, Mg, and K, followed by Zn, Ca, Al, and Fe. Heavy metals, such as Bi or Hg, were also detected. Cluster analysis of the determined elemental concentrations divided them into three distinct groups: Group 1: Ag, As, Bi, Cd, Hg, Mo, Sb, Se, and Zn—the most diverse cluster, representing mostly long-range transported volatile elements, with possible extra local geological sources; Group 2: Al, Fe, Cu, and Mn—elements with crustal sources; and Group 3: Na, Ca, Mg, K, and Sr—with the main source in sea spray aerosol. The latter interpretation was confirmed by the calculation of sea salt contribution based on the composition of mean seawater and the positive significant correlation between their concentrations and the electrical conductivity of snow samples. In the study site, snow was up to six times more efficient in bringing metal pollution into terrestrial environment, when compared to rain.


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