AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Investigation of a Particle into Liquid Sampler to Study the Formation and Ageing of Secondary Organic Aerosol
JACQUELINE HAMILTON, Kelly L. Pereira, Andrew R. Rickard, William J. Bloss, M. Salim Alam, Marie Camredon, Amalia Munoz, Monica Vasquez, Esther Garcia, Mila Rodenas, Teresa Espallardo, University of York
Abstract Number: 757 Working Group: Aerosol Chemistry
Abstract The atmospheric oxidation of Volatile Organic Compounds (VOCs) in the presence of NOx results in the formation of tropospheric ozone and Secondary Organic Aerosol (SOA). Whilst SOA is known to affect both climate and human health, the VOC oxidation pathways leading to SOA formation are poorly understood. This is in part due to the vast number and the low concentration of SOA species present in the ambient atmosphere. Atmospheric simulation chambers such as the EUropean PHOtoREactor (EUPHORE) in Valencia, Spain, are often used to study SOA formation from a single VOC precursor under controlled conditions. SOA composition and formation can be studied using online techniques such as AMS, which provide high time resolution but limited structural information or offline filters samples can provide low time resolution but high chemical complexity.
In this work we report time resolved SOA composition analysis using a Particle into Liquid Sampler (PILS) followed by Liquid Chromatography Ion-Trap Mass Spectrometry and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. Experiments were performed at EUPHORE investigating the formation and composition of Methyl Chavicol SOA. Methyl Chavicol was identified as the highest floral emission from an oil palm plantation in Borneo and has also been observed in US pine forests. Methyl Chavicol oxidation was investigated using a series of photosmog and ozonolysis experiments with varying ratios of NOx:VOC. An extensive range of instruments were used to monitor radical and product formation. Samples were collected using the PILS at 30 minute intervals with filters taken at the end of each experiment for comparison. A number of key oxidation products have been identified and can be compared to model simulations. Time profiles can be used to determine the importance of first, second & higher oxidation products and may indicate which species are undergoing oxidation or heterogeneous reactions during aerosol ageing.