AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Detection of Carbonaceous Aerosols by Using Laser Induced Breakdown Spectroscopy (LIBS)
GIBAEK KIM, Myoseon Jang, Kihong Park, Gwangju Institute of Science and Technology
Abstract Number: 379 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Carbonaceous aerosols that mainly comprise black carbon (BC) and organic carbon (OC) are ubiquitous in the atmosphere. They can affect visibility, radiation balance, and human health. Laser-induced breakdown spectroscopy (LIBS) can be used for multi-elemental analysis of diverse samples either in solid, liquid, or gas phase. In this study, feasibility of the LIBS technique as a tool to determine elemental compositions of carbonaceous aerosols was tested. After various aerosols were collected on the silver membrane filter, the Q-switched Nd:YAG laser was employed as the excitation source (40 mJ/pulse with a pulse width of 4-5 ns at a wavelength of 1064 nm). Repetition rate and delay time were set to be 1 Hz and 1 us, respectively. After laser-induced plasma was generated, the light emitted from the plasma was collected and was then delivered to the spectrometer (190 nm to 884 nm). Emission lines of carbon (247.856 nm), hydrogen (656.286 nm), and oxygen (777.421 nm) were analyzed. During the measurements, argon (99.999%) was used as the surrounding gas to avoid chemical interference caused by pre-existing elements in air. Relationship between nominal atomic ratios (H/C and O/C) of aerosols and LIBS responses were investigated. Chemometric tools such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were applied for further analysis. The data suggest that LIBS coupled with Chemometrics can be used to detect elemental compositions of carbonaceous aerosols and to classify various carbonaceous aerosols according to their classes.