AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Towards a Calibration Procedure for Thermal Optical Analysis
COURTNEY GRIMES, Russell Dickerson, Christopher Zangmeister, Joseph Conny, University of Maryland
Abstract Number: 546 Working Group: Instrumentation and Methods
Abstract Elemental carbon (EC) is a product of incomplete combustion, and EC prevalent in the atmosphere is known to have adverse effects on human health and Earth’s radiation budget. Due to the complex nature of ambient air particles, there is no standard technique for EC measurement. Thermal Optical Analysis (TOA) has been widely used for ambient EC analysis where carbonaceous material is thermally desorbed at different temperature steps. Unlike with other optical methods, TOA does not require an absorption coefficient for mass determination. TOA determines the mass of organic carbon and elemental carbon, but this separation is difficult to define due to charring effects. Currently, the only calibration procedure to determine the instrument’s response involves a known amount of OC (such as sucrose) deposited on a filter. However, there is no calibration procedure for determining the EC quantity. Here, we present data on using a water soluble, commercially available carbon black as a potential material to mimic EC for use in TOA. Different ratios of this surrogate with sucrose were created and analyzed with different temperature protocols to mimic ambient sampling. By introducing known amounts of EC with OC, the EC/TC ratio could be calculated and compared to values determined experimentally.