摘要:

The production of secondary organic aerosol (SOA) by the dark ozonolysis of gas-phase beta-caryophyllene was studied. The experiments were conducted in a continuous-flow environmental chamber for organic particle mass concentrations of 0.5 to 30 mu g m(-3) and with ozone in excess, thereby allowing the study of second-generation particle-phase products under atmospherically relevant conditions. The particle-phase products were characterized by an ultra-performance liquid chromatograph equipped with an electrospray ionization time-of-flight mass spectrometer (UPLC-ESI-ToF-MS). Fragmentation mass spectra were used for the structural elucidation of each product, and the structures were confirmed as consistent with the accurate m/z values of the parent ions. In total, fifteen products were identified. Of these, three are reported for the first time. The structures showed that 9 out of 15 particle-phase products were second generation, including all three of the new products. The relative abundance of the second-generation products was approximately 90% by mass among the 15 observed products. The O:C and H:C elemental ratios of the 15 products ranged from 0.13 to 0.50 and from 1.43 to 1.60, respectively. Fourteen of the products contained 3 to 5 oxygen atoms. A singular product, which was one of the three newly identified ones, had 7 oxygen atoms, including 1 carboxylic group, 2 carbonyl groups, and 3 hydroxyl groups. It was identified as 2, 3-dihydroxy-4-[2-(4-hydroxy-3-oxobutyl)3, 3-dimethylcyclobutyl]-4-oxobutanoic acid (C14H22O7). The estimated saturation vapor pressure of this product is 3.3x10(-13) Pa, making this product a candidate contributor to new particle formation in the atmosphere.

附注:

ISI Document Delivery No.: 705ZOTimes Cited: 12Cited Reference Count: 45Li, Y. J. Chen, Q. Guzman, M. I. Chan, C. K. Martin, S. T.Office of Science (BES), US Department of Energy [DE-FG02-08ER64529]; Hong Kong University of Science and Technology; Research Grants Council of the Hong Kong Special Administrative Region, China [610909]; NASAThis material is based upon work supported by the Office of Science (BES), US Department of Energy, Grant No. DE-FG02-08ER64529. YJL gratefully acknowledges support from the Hong Kong University of Science and Technology Overseas Research Award and the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. 610909). QC acknowledges support from the NASA Earth and Space Science Fellowship. The authors thank Amanda Mifflin, Mackenzie Smith, and Mikinori Kuwata for their support and valuable suggestions as well as Karena McKinney for gas-phase measurements carried out using an Ionic on proton-transfer-reaction mass spectrometer.Copernicus gesellschaft mbhGottingen