Abstract
Using a quartz fiber filter for the PM2.5 carbonaceous measurement causes the adsorption of gaseous organic carbon (OCG) and overestimation of particulate OC (positive artifact). In this study, the filter sampling with and without an activated carbon denuder was simultaneously carried out in Kazo, Saitama Prefecture and the magnitude of the OCG adsorption and its seasonal variation were investigated. The seasonal averages of OCG ranged from 0.26 μg/m3 (autumn) to 0.42 μg/m3 (winter), and the differences between the seasons were small. About 70 to 90% of the OCG exist in the OC1 and OC2. The ratio of OCG in the OC without a denuder was higher when the OC was below 2 μg/m3, and thus the positive artifact became higher in the low OC concentration. Regarding the ratio of OCG in the OC for each fraction, OC1 was higher than the other fractions, but OC2 was also higher. As a trial, in order to estimate the influence of the OCG on the measured OC without a denuder, the formula that calculate the ratio of OCG in the OC from the OC was developed based on the results of this study.
