期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2008
卷号：105
期号：35
页码：12769-12773
DOI：10.1073/pnas.0805255105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Sulfate (SO4) and its precursors are significant components of the atmosphere, with both natural and anthropogenic sources. Recently, our triple-isotope (16O, 17O, 18O) measurements of atmospheric sulfate have provided specific insights into the oxidation pathways leading to sulfate, with important implications for models of the sulfur cycle and global climate change. Using similar isotopic measurements of aerosol sulfate in a polluted marine boundary layer (MBL) and primary sulfate (p-SO4) sampled directly from a ship stack, we quantify the amount of p-SO4 found in the atmosphere from ships. We find that ships contribute between 10% and 44% of the non-sea-salt sulfate found in fine [diameter (D) < 1.5 {micro}m) particulate matter in coastal Southern California. These fractions are surprising, given that p-SO4 constitutes {approx}2-7% of total sulfur emissions from combustion sources [Seinfed JH, Pandis SN (2006) Atmospheric Chemistry and Physics (Wiley-Interscience, New York)]. Our findings also suggest that the interaction of SO2 from ship emissions with coarse hydrated sea salt particles may lead to the rapid removal of SO2 in the MBL. When combined with the longer residence time of p-SO4 emissions in the MBL, these findings suggest that the importance of p-SO4 emissions in marine environments may be underappreciated in global chemical models. Given the expected increase of international shipping in the years to come, these findings have clear implications for public health, air quality, international maritime law, and atmospheric chemistry.
