Secondary formation and the Smoky Mountain organic aerosol: An examination of aerosol polarity and functional group composition during SEAVS
Secondary formation and the Smoky Mountain organic aerosol: An examination of aerosol polarity and functional group composition during SEAVS
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DOI：
10.1021/es970405s
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发表时间：
1998-03-01
影响因子：
11.4
通讯作者：
Turpin, BJ
中科院分区：
文献类型：
--
作者：
Blando, JD;Porcja, RJ;Turpin, BJ
1995 年 7 月至 8 月东南气溶胶和能见度研究 (SEAVS) 期间，在田纳西州 Look Rock 的大烟山收集了尺寸分辨颗粒样品，并通过傅里叶变换红外 (FTIR) 光谱直接分析官能团和化学键信息。还用己烷、丙酮和水轻轻冲洗二十八个样品，并在每次冲洗后重新分析。对用溶剂冲洗的基材进行直接 FTIR 分析，即使样品对于传统提取和分析来说太小（大约 10-15 μg），也可以通过极性进行分离并识别含硫有机物。亚微米有机气溶胶主要是极性的。大多数非极性物质，包括脂肪族碳和各种矿物质，集中在大于 1.0 μm 的颗粒中，很可能来自初级生物和地质排放，例如植物蜡和风吹土壤灰尘。与 Los Angeles 不同，羰基尺寸分布是单峰的，通常在 0.5-1.0 μm 直径尺寸范围内达到峰值。硫酸盐、羰基和有机硫吸光度的优势、气溶胶的极性和羰基尺寸分布表明，二次形成过程对大烟山气溶胶的浓度、成分和尺寸分布有很大影响。
Size-resolved particle samples were collected in the Smoky Mountains at Look Rock, TN, during the Southeastern Aerosol and Visibility Study (SEAVS) July-August 1995 and analyzed directly by Fourier transform infrared (FTIR) spectroscopy for functional group and chemical bond information. Twenty-eight samples were also gently rinsed in hexane, acetone, and water and reanalyzed after each rinse. Direct FTIR analyses of substrates rinsed with solvents enabled separation by polarity and identification of sulfur-containing organics even though samples were too small for traditional extraction and analysis (approximately 10-15 mu g). The submicron organic aerosol was predominantly polar. Most of the nonpolar material, including aliphatic carbon and various minerals, was concentrated in particles greater than 1.0 mu m and is most likely from primary biogenic and geogenic emissions, such as plant waxes and windblown soil dust. Unlike Los Angeles, carbonyl size distributions were unimodal and usually peaked in the 0.5-1.0 mu m diameter size range. The predominance of sulfate, carbonyl, and organosulfur absorbances, the polarity of the aerosol, and the carbonyl size distributions indicate that secondary formation processes have a large influence on the concentrations, composition, and size distributions of the Smoky Mountain aerosol.