Temperature-Dependent Henry鈥檚 Law Constants of Atmospheric Organics of Biogenic Origin
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- 作者：Chunbo Leng ; J. Duncan Kish ; Judas Kelley ; Mindy Mach ; Joseph Hiltner ; Yunhong Zhang ; Yong Liu
- 刊名：Journal of Physical Chemistry A
- 出版年：2013
- 出版时间：October 10, 2013
- 年：2013
- 卷：117
- 期：40
- 页码：10359-10367
- 全文大小：401K
- 年卷期：v.117,no.40(October 10, 2013)
- ISSN：1520-5215
文摘
There have been growing interests in modeling studies to understand oxidation of volatile organic compounds in the gas phase and their mass transfer to the aqueous phase for their potential roles in cloud chemistry, formation of secondary organic aerosols, and fate of atmospheric organics. Temperature-dependent Henry鈥檚 law constants, key parameters in the atmospheric models to account for mass transfer, are often unavailable. In the present work, we investigated gas鈥搇iquid equilibriums of isoprene, limonene, 伪-pinene, and linalool using a bubble column technique. These compounds, originating from biogenic sources, were selected for their implications in atmospheric cloud chemistry and secondary organic aerosol formation. We reported Henry鈥檚 law constants (KH), first order loss rates (k), and gas phase diffusion coefficients over a range of temperatures relevant to the lower atmosphere (278鈥?98 K) for the first time. The measurement results of KH values for isoprene, limonene, 伪-pinene, and linalool at 298 K were 0.036 卤 0.003; 0.048 卤 0.004; 0.029 卤 0.004; and 21.20 卤 0.30 mol L鈥? atm鈥?, respectively. The fraction for these compounds in stratocumulus and cumulonimbus clouds at 278 K were also estimated in this work (isoprene, 1.0 脳 10鈥?, 6.8 脳 10鈥?; limonene, 1.5 脳 10鈥?, 1.0 脳 10鈥?; 伪-pinene, 4.5 脳 10鈥?, 3.1 脳 10鈥?; and linalool, 6.2 脳 10鈥?, 4.2 脳 10鈥?). Our measurements in combination with literature results indicated that noncyclic alkenes could have smaller KH values than those of cyclic terpenes and that KH values may increase with an increasing number of double bonds. It was also shown that estimated Henry鈥檚 law constants and their temperature dependence based on model prediction can differ from experimental results considerably and that direct measurements of temperature-dependent Henry鈥檚 law constants of atmospheric organics are necessary for future work.