Multiple sulfur isotopes （32S, 335, 345, 365） and oxygen isotopes （160, 180） in Beijing aerosols were measured with MAT-253 isotope mass spectrometer. The δ345 values of Beijing aerosol samples range from 1.68%o ...Multiple sulfur isotopes （32S, 335, 345, 365） and oxygen isotopes （160, 180） in Beijing aerosols were measured with MAT-253 isotope mass spectrometer. The δ345 values of Beijing aerosol samples range from 1.68%o to 12.57%o with an average value of 5.86%0, indicating that the major sulfur source is from direct emission during coal combustion. The c5180 values vary from -5.29%0 to 9.02%0 with an average value of 5.17%o, revealing that the sulfate in Beijing aerosols is mainly composed of the secondary sulfate. The main heterogeneous oxidation of SO2 in atmosphere is related to H202 in July and August, whereas H202 oxidation and Fe3＋ catalytic oxidation with SO2 exist simultaneously in September and October. Remarkable sulfur iso- tope mass-independent fractionation effect is found in Beijing aerosols, which is commonly attributed to the photochemical oxidation of SO2 in the stratosphere. In addition, thermochemical reactions of sulfur-bearing compounds might be also a source of sulfur isotope anomalies based on the correlation between A335 and CAPE.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.41240025 and 41373023)Start-up Foundation of the Ministry of Education for Overseas Returnees(Grant No.2012s001)Prospective Researching Project of Industry-University-Research of Jiangsu Province(Grant No.BY2013007-03)
文摘Multiple sulfur isotopes （32S, 335, 345, 365） and oxygen isotopes （160, 180） in Beijing aerosols were measured with MAT-253 isotope mass spectrometer. The δ345 values of Beijing aerosol samples range from 1.68%o to 12.57%o with an average value of 5.86%0, indicating that the major sulfur source is from direct emission during coal combustion. The c5180 values vary from -5.29%0 to 9.02%0 with an average value of 5.17%o, revealing that the sulfate in Beijing aerosols is mainly composed of the secondary sulfate. The main heterogeneous oxidation of SO2 in atmosphere is related to H202 in July and August, whereas H202 oxidation and Fe3＋ catalytic oxidation with SO2 exist simultaneously in September and October. Remarkable sulfur iso- tope mass-independent fractionation effect is found in Beijing aerosols, which is commonly attributed to the photochemical oxidation of SO2 in the stratosphere. In addition, thermochemical reactions of sulfur-bearing compounds might be also a source of sulfur isotope anomalies based on the correlation between A335 and CAPE.
