AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Comparison of Ambient Absorption Measured Using a CAPS PMssa Monitor and AE33 Aethalometer at DEM GAW Athens
Stergios Vratolis, Timothy Onasch, Kostas Eleftheriadis, ANDREW FREEDMAN, Aerodyne Research, Inc.
Abstract Number: 267 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Direct in situ measurements of the aerosol absorption coefficient are difficult to achieve with high accuracy and confidence for ambient conditions. Among all available optical absorption or light attenuation methods, the Aethalometer is the most frequently used technique to measure real-time BC mass concentrations and subsequently atmospheric absorption coefficients. In contrast, a newly available instrument, the CAPS PMssa, which simultaneously measures the total aerosol extinction and scattering coefficients on the same sample volume, has the capability of directly providing the absorption coefficient by subtraction. We present absorption measurements obtained using this instrument and those obtained by a new Aethalometer model (AE33), which attempts to correct the “spot loading effect” evident in previous models. These continuing measurements were performed at the DEM GAW station in Athens, Greece starting in August 2014. During this period, the station was mainly influenced by local contamination sources (predominantly vehicle emissions from the city center and Piraeus port). For the most part, within the uncertainties associated with the both instruments, the agreement is good. A notable diurnal cycle is observed in data from both instruments corresponding to the morning and evening traffic rush hours. This is a result partly explained by the formation and transport mechanisms known to govern the occurrence of carbon containing particles