Effective Vertical Transport of Particulate Organic Carbon in the Western North Pacific Subarctic Region

Abstract. Biomass burning (BB) largely modifies the chemical composition of atmospheric aerosols on the globe. We collected aerosol samples (TSP) at Cape Hedo, on subtropical Okinawa Island, from October 2009 to February 2012 to study anhydrosugars as BB tracers. Levoglucosan was detected as the dominant anhydrosugar followed by its isomers, mannosan and galactosan. We found a clear seasonal trend of levoglucosan and mannosan with winter maxima and summer minima. Positive correlation was found between levoglucosan and nss-K+ (r = 0.38, p < 0.001); the latter is another BB tracer. The analyses of air mass trajectories and fire spots demonstrated that the seasonal variations of anhydrosugars are caused by long-range transport of BB emissions from the Asian continent. We found winter maxima of anhydrosugars, which may be associated with open burning and domestic heating and cooking in northern and northeastern China, Mongolia and Russia and with the enhanced westerly winds. The monthly averaged levoglucosan / mannosan ratios were lower (2.1–4.8) in May–June and higher (13.3–13.9) in November–December. The lower values may be associated with softwood burning in northern China, Korea and southwestern Japan whereas the higher values are probably caused by agricultural waste burning of maize straw in the North China Plain. Anhydrosugars comprised 0.22% of water-soluble organic carbon (WSOC) and 0.13% of organic carbon (OC). The highest values to WSOC (0.37%) and OC (0.25%) were found in winter, again indicating an important BB contribution to Okinawa aerosols in winter. This study provides useful information to better understand the effect of East Asian biomass burning on the air quality in the western North Pacific Rim.

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Bacterial carbon content and the living and detrital bacterial contributions to suspended particulate organic carbon in the North Pacific Ocean

Aquatic Microbial Ecology ◽

10.3354/ame01462 ◽

2011 ◽

Vol 62 (2) ◽

pp. 165-176 ◽

Cited By ~ 27

Author(s):

N Kawasaki ◽

R Sohrin ◽

H Ogawa ◽

T Nagata ◽

R Benner

Keyword(s):

Pacific Ocean ◽

Organic Carbon ◽

Carbon Content ◽

Particulate Organic Carbon ◽

North Pacific ◽

North Pacific Ocean ◽

The North ◽

Suspended Particulate ◽

The North Pacific

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Effect of biomass burning over the western North Pacific Rim: wintertime maxima of anhydrosugars in ambient aerosols from Okinawa

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-25581-2014 ◽

2014 ◽

Vol 14 (18) ◽

pp. 25581-25616 ◽

Cited By ~ 4

Author(s):

C. Zhu ◽

K. Kawamura

Keyword(s):

Organic Carbon ◽

Biomass Burning ◽

Atmospheric Aerosols ◽

North Pacific ◽

Western North Pacific ◽

North China ◽

Water Soluble ◽

Pacific Rim ◽

Chemical Compositions ◽

Okinawa Island

Abstract. Biomass burning (BB) largely modifies the chemical compositions of atmospheric aerosols on the globe. We collected aerosol samples (TSP) at Cape Hedo, subtropical Okinawa Island from October 2009 to February 2012 to study anhydrosugars as BB tracers. Levoglucosan was detected as the dominant anhydrosugar followed by its isomers, mannosan and galactosan. We found a clear seasonal trend of levoglucosan and mannosan with winter maxima and summer minima. Positive correlation was found between levoglucosan and nss-K+ (r = 0.38, p < 0.001); the latter is another BB tracer. The analyses of air mass trajectories and fire spots demonstrated that the seasonal variations of anhydrsosugsars are caused by a long-range transport of BB emissions from the Asian continent. We found winter maxima of anhydrosugars, which may be associated with open burning and domestic heating and cooking in north and northeast China, Mongolia and Russia and with the enhanced westerly. The monthly averaged levoglucosan/mannosan ratios were lower (2.1–4.8) in May–June and higher (13.3–13.9) in November–December. The lower values may be associated with softwood burning in north China, Korea and southwest Japan whereas the higher values are probably caused by agriculture waste burning of maize straw in the North China Plain. Anhydrosugars comprised 0.22% of water-soluble organic carbon (WSOC) and 0.13% of organic carbon (OC). The highest values to WSOC (0.37%) and OC (0.25%) were found in winter, again indicating an important BB contribution to Okinawa aerosols in winter. This study provides useful information to better understand the effect of East Asian biomass burning on the air quality in the western North Pacific Rim.

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Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-3037-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 3037-3049 ◽

Cited By ~ 120

Author(s):

Y. Miyazaki ◽

K. Kawamura ◽

J. Jung ◽

H. Furutani ◽

M. Uematsu

Keyword(s):

Organic Carbon ◽

North Pacific ◽

Western North Pacific ◽

Organic Nitrogen ◽

Biological Activities ◽

Organic Aerosols ◽

Total Carbon ◽

Isotopic Ratios ◽

Study Region ◽

Marine Biological

Abstract. Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON) and organic carbon (OC) as well as isotopic ratios of total nitrogen (TN) and total carbon (TC). Increased concentrations of methanesulfonic acid (MSA) and diethylammonium (DEA+) at 40–44° N and subtropical regions (10–20° N) together with averaged satellite chlorophyll-a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION) was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios (δ13C) indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C showed higher values (from −22 to −20‰) when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC) ratios tended to increase with increasing local wind speeds, indicating that sea-to-air emissions of ON via sea spray contribute significantly to the marine organic aerosols over the study region.

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Long-term (2001–2012) trends of carbonaceous aerosols from a remote island in the western North Pacific: an outflow region of Asian pollutants

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-1291-2018 ◽

2018 ◽

Vol 18 (2) ◽

pp. 1291-1306 ◽

Cited By ~ 16

Author(s):

Suresh K. R. Boreddy ◽

M. Mozammel Haque ◽

Kimitaka Kawamura

Keyword(s):

Organic Carbon ◽

Long Range ◽

North Pacific ◽

Western North Pacific ◽

Atmospheric Transport ◽

Carbonaceous Aerosols ◽

Central Pacific ◽

Air Masses ◽

Photochemical Formation

Abstract. The present study reports on long-term trends of carbonaceous aerosols in total suspended particulate (TSP) samples collected at Chichijima in the western North Pacific during 2001–2012. Seasonal variations of elemental carbon (EC), organic carbon (OC), and water-soluble organic carbon (WSOC) concentrations showed maxima in winter to spring and minima in summer. These seasonal differences in the concentrations of carbonaceous aerosols were associated with the outflows of polluted air masses from East Asia, which are clearly distinguishable from pristine air masses from the central Pacific. The higher concentrations of carbonaceous aerosols during winter to spring are associated with long-range atmospheric transport of East Asian continental polluted air masses, whereas lower concentrations may be due to pristine air masses from the central Pacific in summer. The annual trends of OC ∕ EC (+0.46 % yr−1), WSOC (+0.18 % yr−1) and WSOC ∕ OC (+0.08 % yr−1) showed significant (p  <  0.05) increases during the period of 2001–2012, suggesting that photochemical formation of WSOC and its contributions to secondary organic aerosols (SOAs) have increased over the western North Pacific via long-range atmospheric transport. We found a significant increase (+0.33 % yr−1) in nss-K+ ∕ EC ratios, demonstrating that concentrations of biomass-burning-derived carbonaceous aerosols have increased, while those of primary fossil-fuel-derived aerosols have decreased over the western North Pacific. Further, secondary biogenic emissions are also important over the western North Pacific as inferred from a significant increase (+0.14 % yr−1) in the concentrations of methanesulfonate (MSA−, a tracer for biogenic sources). This point was further supported by a moderate correlation (r = 0.40) between WSOC and MSA−. We also found a significant increase in OC ∕ TC (total carbon) and WSOC ∕ TC ratios, further suggesting that photochemical formation of WSOC and its contributions to SOAs have increased over the western North Pacific during 2001–2012 via long-range atmospheric transport from East Asia.

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