Impact of transport of sulfur dioxide from the Asian continent on the air quality over Korea during May 2005

The East Asian countries have been affected by atmospheric gaseous pollutants (in particular SO2) transported from the Asian continent as well as Asian dust storms. For investigation of the impact of these anthropogenic trace gases on local air quality in Korea, ground-based measurements using a Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) system and in situ gas analyzers as well as synoptic meteorological data and scattered sunlight spectra obtained by the satellite-borne instrument, Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) launched on board of Environmental Satellite (ENVISAT) in March 2002, were utilized to retrieve SO2 and trace its transport from the Asian continent to Korea in May 2005. The ground-based measurements were carried out in the region of interest, at Korea Global Watch Observatory (KGAWO) in Korea. Plumes of high SO2 over Chinese industrial areas and their transport to the Korean peninsula were observed in SCIAMACHY data in the period of 21–26 May 2005. Highly increased SO2 was measured by the MAX-DOAS system and in situ gas analyzer in the period of 27–29 May 2005 at KGAWO. These observations are supported by the meteorological results that the air-masses picking up these high SO2 plumes while passing over the Chinese industrial and metropolitan areas were transported to the Korean peninsula. The tropospheric SO2 VCDs over these Chinese industrial and metropolitan areas ranged up to 1.4×1017 mol cm−2 in SCIAMACHY data. These SO2 plumes resulted in increased SO2 surface levels of up to 7.8 ppbv (measured by an in situ gas analyzer) at KGAWO.