Ultra-High Resolution Detection And Characterization Of Organosulfate In Arctic And Antarctic Atmospheric Aerosols

Organosulfates(OSs),as a newly-indentified but important class of secondary organic aerosol(SOA),have been found ubiquitous in fine particulate matter.Because of their amphipathy and light absorption,OSs have the potential impact on climate by affecting the aerosol hygroscopocity and optical properties.Combining labrotory studies and field studies,the variety of OSs can serve as molecular tracers for precursors and multiphase processes leading to SOA.The polar environment is sensitive to pertubations of the radiative budget and vulnerable to the extraneous contamination.OSs have been detected in the Arctic atmospheric aerosols,compromising 7%～20%of total OAs.However,the investigation of OSs in the polar areas is still rare,as well as their formation and influence in the polar areas.Here we report the OSs from Arctic and Antarctic atmosphere using Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)coupled with negative ion mode electrospray ionization(ESI(-))during the 6th Chinese National Arctic Research Expedition and 30th Chinese National Antarctic Research Expedition(CHINARE).This study provides the important and valuble data of OSs in the polar atmosphere,and promotes the understanding of their characteristics,sources and formations.We found that:1.Hundreds to thousands of organic compounds were detected in the polar areas.The formula number of S-containing organic compounds accounted for 32%-55%of the total organic compounds,much more than the values reported in the previos studies.2.The formula number of OSs took up 71%-88%of the S-containing organic formulas and the estimated concentrations of total OSs were in the range of 46-670 ng/m3 and 47-260 ng/m3 in the Arctic and Antarctic sampling area,respectively,accounting for 1-16%of total OMp.OSs were found to have undergone a high degree of oxidation in the aerosol samples,which might be due to the combined effects of enhanced photo-oxidation in summertime or continuous oxidation during transport to the polar region.3.The potential appointment of OS precursors highlights the important role of long-range air-mass transport on the OSs derived from biogenic precursors and a notably large contribution from anthropogenic emissions,suggesting that human activities have significant impacts in remote polar environments.The results of this study provide important insights into the characteristics of OSs in the polar atmosphere.However,the need for further research focusing on the quantification,formation mechanisms and impacts of OSs on climate is emphasized.