Department of Chemical and Environmental Engineering, University of California-Riverside , Riverside, California United States.
Environ Sci Technol. 2013 Oct 1;47(19):10980-6. doi: 10.1021/es401867j. Epub 2013 Sep 10.
This study examines the hygroscopic and surface tension properties as a function of photochemical aging of the aerosol emissions from biomass burning. Experiments were conducted in a chamber setting at the UC-Riverside Center for Environmental Research and Technology (CE-CERT) Atmospheric Processes Lab using two biomass fuel sources, manzanita and chamise. Cloud condensation nuclei (CCN) measurements and off-line filter sample analysis were conducted. The water-soluble organic carbon content and surface tension of the extracted filter samples were measured. Surface tension information was then examined with Köhler theory analysis to calculate the hygroscopicity parameter, κ. Laboratory measurement of biomass burning smoke from two chaparral fuels is shown to depress the surface tension of water by 30% or more at organic matter concentrations relevant at droplet activation. Accounting for surface tension depression can lower the calculated κ by a factor of 2. This work provides evidence for surface tension depression in an important aerosol system and may provide closure for differing sub- and supersaturated κ measurements.
本研究考察了气溶胶排放物的吸湿性和表面张力特性，这些排放物是生物质燃烧的光化学老化的函数。实验在加州大学河滨分校环境研究与技术中心（CE-CERT）大气过程实验室的室条件下进行，使用了两种生物质燃料，曼萨尼塔和查米塞。进行了云凝结核（CCN）测量和离线过滤器样品分析。测量了提取的过滤器样品中的水溶性有机碳含量和表面张力。然后，使用克勒尔理论分析来检查表面张力信息，以计算吸湿性参数κ。实验测量了两种矮灌丛燃料的生物质燃烧烟雾，结果表明，在与液滴激活相关的有机物浓度下，水的表面张力降低了 30%以上。考虑到表面张力的降低，计算出的κ 值可降低 2 倍。这项工作为重要气溶胶系统中的表面张力降低提供了证据，并可能为不同的亚饱和和过饱和κ 值测量提供了封闭性。
