Episodic Particulate Sulfate and Sulfur Dioxide on the Southwestern Japan Coast in March and April 2010
Particulate sulfate in PM2.5, sulfur dioxide (SO2) and size-segregated aerosol particle number concentrations were measured at a site (32°19′N, 129°59′E) on the southwestern Japan coast from 5 March to 10 April, 2010. Results show frequent episodic increases of sulfate and SO2. Compared to the avera...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Springer
2012-03-01
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| Series: | Asian Journal of Atmospheric Environment |
| Subjects: | |
| Online Access: | http://asianjae.org/_common/do.php?a=full&b=11&bidx=1573&aidx=19857 |
| Summary: | Particulate sulfate in PM2.5, sulfur dioxide (SO2) and size-segregated aerosol particle number concentrations were measured at a site (32°19′N, 129°59′E) on the southwestern Japan coast from 5 March to 10 April, 2010. Results show frequent episodic increases of sulfate and SO2. Compared to the average concentration of sulfate 4.4±2.7 μg m-3 in the whole observation period, episodic sulfate reached 10.5-20.1 μg m-3. The variation of sulfate always synchronized with aerosol particles in the size range of 0.1-0.5 μm, indicating the episodic sulfate was a consequence of the increase of the sub-micron particles. SO2 did not have remarkable increase in any episodes of sulfate increase. During the passage of low pressure systems which loaded Asian dust in postfrontal air, concentrated sulfate appeared right behind the front but before dust arrival, suggesting the dominance of dustfree particulate sulfate. Weather and backward trajectory analyses revealed that air parcels with high sulfate passed eastern and northeastern China or Korean peninsula before arriving at the site. In contrast, those with high SO2 passed an active volcano, Mt. Sakurajima, about 100 km in the south, suggesting the SO2 was more likely from the volcanic emission. The ratio of sulfate to total sulfur compounds (SO42-)/(SO42-+SO2) was 0.31-0.89 in continentally originated air while was 0.25-0.43 in the air having passed the volcano, showing more efficient conversions of SO2 to sulfate in the air from the continent. The close dependence of the conversion on humidity in the continentally originated air was confirmed. |
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| ISSN: | 1976-6912 2287-1160 |