Comparison of Organic Carbon Measurement Method of Fine Particles using Multi-Channel Denuders

Abstract

This paper describes an evaluation of the organic carbon concentrations on fine particles (PM_2.5) using commercially available multi-channel denuder samplers. Three different sampling systems — filter sampling as the typical method (reference), a KI-denuder for removing ozone, and a XAD4-denuder for trapping gaseous semi-volatile organic compounds — were selected and demonstrated for the collection of PM_2.5 sample during the summer of 2004 in Saitama in Japan. The results of the comparison between reference samples and KI-denuded samples suggest that the organic carbon (OC) were not susceptible to ozone degradation although relatively high ozone atmospheric concentrations (O₃ for 12 h averages: 5-65 ppb) were observed during the sampling periods (< 12 h). The comparison between the reference samples and XAD4-denuder samples results indicated that semi-volatile organic carbon (SVOC) had a significant effect on the organic carbon concentration. Positive artifact, adsorptions on typical filtering samples were estimated to be 2.3 ± 0.7 μgC/m³ which was similar to the calculated capacity of the adsorbed organic vapor on a quartz filter.