Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia
Abstract We investigated the changes in the carbonaceous-aerosol sources and their effects on the long-term elemental carbon (EC) and organic carbon (OC) concentration trends at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) in Okinawa, Japan, during the period 2004–2013. We obtain...
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| Format: | Article |
| Language: | English |
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2021-05-01
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| Series: | Aerosol and Air Quality Research |
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| Online Access: | https://doi.org/10.4209/aaqr.200505 |
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| author | Kojiro Shimada Akinori Takami Takatsugu Ishida Yuta Taniguchi Shuichi Hasegawa Chak K. Chan Yong Pyo Kim Neng-Huei Lin Shiro Hatakeyama |
| author_facet | Kojiro Shimada Akinori Takami Takatsugu Ishida Yuta Taniguchi Shuichi Hasegawa Chak K. Chan Yong Pyo Kim Neng-Huei Lin Shiro Hatakeyama |
| author_sort | Kojiro Shimada |
| collection | DOAJ |
| description | Abstract We investigated the changes in the carbonaceous-aerosol sources and their effects on the long-term elemental carbon (EC) and organic carbon (OC) concentration trends at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) in Okinawa, Japan, during the period 2004–2013. We obtained the EC and OC concentrations by conducting semi-real-time measurements using a carbon monitor, and performing an offline thermal/optical filter analysis according to the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol. The annual average concentration of the EC remained constant between 2004 and 2013, but that of the OC decreased at a rate of 0.11 µg C m−3 y−1 (α > 0.05). The secondary OC (SOC)/OC ratio showed an increasing trend from 2004 till 2011, which may have been caused by a reduction in primary emissions of OC and compositional changes in the organic compounds originating in China, from which air pollutants were frequently transported during spring and winter. Although the EC concentration did not change appreciably in either season, the OC concentration decreased at rates of 0.10 µg C m−3 y−1 and 0.11 µg C m−3 y−1 during spring and winter, respectively. We estimated the contributions from the various sources of carbonaceous aerosol, viz., biomass burning, fossil-fuel combustion, and air-pollutant transport from China, based on the OC/EC ratio, which decreased from 5.7 to 2.4 in terms of the annual average. The growing share from fossil-fuel combustion is responsible for the decline in biofuel-burning OC emissions transported from China to CHAAMS. |
| format | Article |
| id | doaj-art-cc896ec7c54d4f498794a37c2428ad3b |
| institution | Kabale University |
| issn | 1680-8584 2071-1409 |
| language | English |
| publishDate | 2021-05-01 |
| publisher | Springer |
| record_format | Article |
| series | Aerosol and Air Quality Research |
| spelling | doaj-art-cc896ec7c54d4f498794a37c2428ad3b2025-02-09T12:21:33ZengSpringerAerosol and Air Quality Research1680-85842071-14092021-05-0121911410.4209/aaqr.200505Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East AsiaKojiro Shimada0Akinori Takami1Takatsugu Ishida2Yuta Taniguchi3Shuichi Hasegawa4Chak K. Chan5Yong Pyo Kim6Neng-Huei Lin7Shiro Hatakeyama8Global Innovation Research Organization, Tokyo University of Agriculture and TechnologyNational Institute for Environmental StudiesInstitute of Agriculture, Graduate School of Tokyo University of Agriculture and TechnologyInstitute of Agriculture, Graduate School of Tokyo University of Agriculture and TechnologyCenter for Environmental Science in SaitamaSchool of Energy and Environment, City University of Hong KongGlobal Innovation Research Organization, Tokyo University of Agriculture and TechnologyGlobal Innovation Research Organization, Tokyo University of Agriculture and TechnologyGlobal Innovation Research Organization, Tokyo University of Agriculture and TechnologyAbstract We investigated the changes in the carbonaceous-aerosol sources and their effects on the long-term elemental carbon (EC) and organic carbon (OC) concentration trends at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) in Okinawa, Japan, during the period 2004–2013. We obtained the EC and OC concentrations by conducting semi-real-time measurements using a carbon monitor, and performing an offline thermal/optical filter analysis according to the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol. The annual average concentration of the EC remained constant between 2004 and 2013, but that of the OC decreased at a rate of 0.11 µg C m−3 y−1 (α > 0.05). The secondary OC (SOC)/OC ratio showed an increasing trend from 2004 till 2011, which may have been caused by a reduction in primary emissions of OC and compositional changes in the organic compounds originating in China, from which air pollutants were frequently transported during spring and winter. Although the EC concentration did not change appreciably in either season, the OC concentration decreased at rates of 0.10 µg C m−3 y−1 and 0.11 µg C m−3 y−1 during spring and winter, respectively. We estimated the contributions from the various sources of carbonaceous aerosol, viz., biomass burning, fossil-fuel combustion, and air-pollutant transport from China, based on the OC/EC ratio, which decreased from 5.7 to 2.4 in terms of the annual average. The growing share from fossil-fuel combustion is responsible for the decline in biofuel-burning OC emissions transported from China to CHAAMS.https://doi.org/10.4209/aaqr.200505Carbonaceous aerosolCHAAMSFossil fuel combustionBiomass burningLong-term trend |
| spellingShingle | Kojiro Shimada Akinori Takami Takatsugu Ishida Yuta Taniguchi Shuichi Hasegawa Chak K. Chan Yong Pyo Kim Neng-Huei Lin Shiro Hatakeyama Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia Aerosol and Air Quality Research Carbonaceous aerosol CHAAMS Fossil fuel combustion Biomass burning Long-term trend |
| title | Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia |
| title_full | Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia |
| title_fullStr | Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia |
| title_full_unstemmed | Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia |
| title_short | Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia |
| title_sort | long term measurements of carbonaceous aerosol at cape hedo okinawa japan effects of changes in emissions in east asia |
| topic | Carbonaceous aerosol CHAAMS Fossil fuel combustion Biomass burning Long-term trend |
| url | https://doi.org/10.4209/aaqr.200505 |
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