Abstract
In order to monitor highly time-resolved and wide-ranged behavior of Elemental Carbon (EC), a thermal analysis method has been developed to determine EC content in aerosols collected on the filter-tape mounted in automated aerosol (less than 10μm in diameter: refereed to as Suspended Particulate Matter, SPM), monitors. The monitor, utilizing β-ray absorption of collected SPM on glass-fiber filter reinforced with acrylic resin binder, is widely used in ambient air quality monitoring stations in apan. For subsequent EC analysis, punched-out sports of filter loaded with particles were thermally treated to remove acrylic resin and organic aerosols simultaneously. The optimal condition determined was instantaneous pyrolysis in Helium atmosphere at 640°C for five minutes. Determined EC concentration by the method showed good correlation with that from SPM samples collected on quartz-filter but was systematically less than that. An extensive measurement of EC over the Kanto Plain, Japan has been conducted by using filter-tape samples in SPM monitors collected from 37 monitoring stations, and quartz-fiber samples collected at five sites during intensive field study period. This revealed the two dimensional distribution of EC showing the formation and dissipation of high concentration area (maximum concentration of 130μg Cm-3) having 50 km in diameter.
