AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
A New Instrument and Method for the Speciation of Carbonaceous Aerosols
MARTIN RIGLER, Luka Drinovec, Athanasia Vlachou, Giulia Stefenelli, Jay G. Slowik, Andre S.H. Prévôt, Anthony D.A Hansen, Iasonas Stavroulas, Jean Sciare, Griša Močnik, Aerosol d.o.o.
Abstract Number: 119 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Carbonaceous aerosols account for a large and often dominant fraction of fine particulate matter (PM2.5) and are extremely diverse in composition. We present a new real-time method which combines an optical method for measuring black carbon (BC) by the Aethalometer (AE33 model), with a thermal method for total carbon (TC) determination, performed by the newly developed Total Carbon Analyzer (TCA). Organic carbon (OC) is calculated as OC = TC - b·BC, where b·BC is equivalent to elemental carbon (EC) and the determined proportionality parameter b is region and/or site specific.
The TCA operates on the principle of rapid combustion of carbonaceous PM collected on a quartz fiber filter to create a pulse of combustion products which are converted to CO2. This pulse is detected as a large transient increase above the CO2 level in ambient air, which is used as the carrier gas. Unlike most OC/EC instruments that make use of thermal-optical methods for the analysis of carbonaceous PM, the TCA does not require special high purity gases or fragile quartz glass components for its operation.
The TC-BC method with the new TCA instrument was tested in field campaigns in Zurich (urban background) and Magadino (rural background), Switzerland; and in Ljubljana (urban background), Slovenia. The carbonaceous fractions in PM2.5 were determined with the TCA with a time resolution of 1 hour, combined with AE33 Aethalometer data on a 1-minute time-base. In parallel, 24h filter samples were collected at both stations for OC/EC laboratory analysis. Additional measurements with AMS (at Swiss sites) and ACSM (in Ljubljana) provided OM concentration (converted to OC) data with high time resolution. The results show a good correlation between 24 h averages of BC and EC (EUSAAR2), and between TC obtained by TCA and TC = OC + EC determined from the 24h filters.