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Abstract
We investigated the contribution of volatile aerosols in light-absorption measurement by three filter-based optical instruments [aethalometer, continuous light-absorption photometer (CLAP), and continuous soot monitoring system (COSMOS)] at Gosan Climate Observatory (GCO) from February to June 2012. The aerosol absorption coefficient ([sigma] ^sub abs^) and the equivalent black carbon (BC) mass concentration (M ^sub BC^) measured by the aethalometer and CLAP showed good agreement with a difference of 9 %, which is likely due to the instrumental uncertainty. However, [sigma] ^sub abs^ and M ^sub BC^ measured by the COSMOS with a heated inlet were found to be approximately 44 and 49 % lower than those measured by the aethalometer and CLAP under ambient conditions, respectively. This difference can be attributed to the light absorption by the volatile aerosols coexisting with the BC. Even considering inherent observational uncertainty, it suggests that approximately 35-40 % difference in the [sigma] ^sub abs^ and M ^sub BC^ can be contributed by volatile aerosols. Increase in the difference of M ^sub BC^ measured by the aethalometer and COSMOS with the increasing thermal organic carbon (OC) measured by Sunset OC/EC analyzer further suggests that the filter-based optical instruments without the use of a heater are likely to enhance the value of [sigma] ^sub abs^ and M ^sub BC^, because this sample air may contain both BC and volatile aerosols. [PUBLICATION ABSTRACT]