AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Potential Aerosol Mass (PAM) Chamber Measurement in the Ambient Air for the Secondary Aerosol Formation and Oxidation Potential of Air Masses Transported from Korea and China
EUNHA KANG, William Brune, Taehyoung Lee, Joon-young Ahn, Meehye Lee, Korea University, South Korea
Abstract Number: 312 Working Group: Aerosol Chemistry
Abstract Potential Aerosol Mass (PAM) chamber measurement in the ambient air was performed in Baek-young Island, South Korea in August 2011 to study the secondary aerosol formation and oxidation potential of air masses transported from China and the Korean Peninsula. The site is situated in the northernmost island of South Korea in the yellow sea, which is only distanced 740 km from Beijing, China and 211 km from Seoul, Korea. The PAM chamber was a small flow-through photo-oxidation cylinder made with aluminum body and ultraviolet lamps in order to continuously photo-oxidize the sample air at high concentration of OH and O3. The OH exposure was similar to about 5 days of the integrated OH exposure for typical atmospheric OH concentration. The ambient air mass was photo-oxidized by passing through the PAM chamber and then the PAM-through aerosols were measured by the High Resolution-Time of Flight-Aerosol Mass Spectrometer (HR-ToF-AMS) and Scanning Mobility Particle Sizer (SMPS). The ambient aerosol was measured with same instruments alternately with PAM aerosol every 6 minutes. Both PAM aerosol and ambient aerosol were sampled through a PM1.0 cyclone.
The results cover the mass concentration and the size distribution of aerosols and major components such as sulfate, ammonium, nitrate and organics for two episodes; organic dominant and sulfate dominant episodes. Organic dominant episode showed the increase of highly oxygenated organic aerosols (OOAs) (e.g. m/z 44) and the formation of sulfates in PAM from the relatively fresh air masses, which was fast transported from the Korean Peninsula. Sulfate dominant episode was characterized to the no increase of OOAs in PAM due to the relatively aged air masses, which was slowly transported from China. The detailed size distribution of PAM and ambient aerosols will be further discussed regarding the possible mixing state of aerosols.