AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Sources and Processes of Submicron Particles at an Urban Downwind Location - Long Island New York
SHAN ZHOU, Jianzhong Xu, Fan Mei, Jian Wang, Arthur J. Sedlacek, Stephen Springston, Yin-Nan Lee, Qi Zhang, University of California, Davis
Abstract Number: 503 Working Group: Remote and Regional Atmospheric Aerosols
Abstract The Department of Energy (DOE) sponsored Aerosol Life Cycle Intensive Operational Period (ALC-IOP) field campaign took place at Brookhaven National Laboratory (BNL) on Long Island, New York, from July 1 to August 15, 2011. An Aerodyne High-Resolution Time-of-flight Aerosol Mass Spectrometer (AMS) was deployed after a temperature-stepping thermodenuder during this study to acquire highly time resolved data on the mass-based size distribution, chemical composition, and volatility profile of the non-refractory species in submicron particles (NR-PM$_(n1)). The average mass concentration of NR-PM$_(n1) was 15.3 (±8.9) microgram per cubic meter, with organics (64.8%) and sulfate (24.2%) dominating the composition. Back trajectory analysis showed that particles observed at Long Island were influenced by heavily polluted urban plumes from New York City, regional eastern US pollutions enriched of ammonium sulfate and LV-OOA, forest fire plumes transported from Canada, and relatively clean air mass form ocean emissions. Positive Matrix Factorization analysis of the high-resolution mass spectra of organics identified three distinct secondary OA factors: a highly oxidized oxygenated LV-OOA (O/C = 0.79), a semi-volatile SV-OOA (O/C = 0.41) and a nitrogen-enriched NOA (O/C = 0.15 and N/C = 0.185). According to the average volatility profile of individual aerosol component, LV-OOA was less volatile than nitrate but more volatile than sulfate. NOA, which appeared to be mainly composed of amine salts according to its high resolution mass spectrum, was less volatile than ammonium nitrate but had a similar volatility profile as organic nitrate. The volatility of SV-OOA was comparable to that of ammonium nitrate and both showed a strong diurnal variation pattern that was higher during the night and early morning and lower during the day. Based on these results, we will discuss the sources and processes of OA in this urban downwind location.