...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Atmospheric chemistry and physics >Towards closing the gap between hygroscopic growth and activation for secondary organic aerosol: Part 1-Evidence from measurements
【24h】

Towards closing the gap between hygroscopic growth and activation for secondary organic aerosol: Part 1-Evidence from measurements

机译：试图缩小吸湿性生长与次要有机气溶胶活化之间的差距：第1部分：测量证据

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Secondary Organic Aerosols (SOA) studied in previous laboratory experiments generally showed only slight hygroscopic growth, but a much better activity as a CCN (Cloud Condensation Nucleus) than indicated by the hygroscopic growth. This discrepancy was examined at LACIS (Leipzig Aerosol Cloud Interaction Simulator), using a portable generator that produced SOA particles from the ozonolysis of α-pinene, and adding butanol or butanol and water vapor during some of the experiments. The light scattering signal of dry SOA-particles was measured by the LACIS optical particle spectrometer and was used to derive a refractive index for SOA of 1.45. LACIS also measured the hygroscopic growth of SOA particles up to 99.6% relative humidity (RH), and a CCN counter was used to measure the particle activation. SOA-particles were CCN active with critical diameters of e.g. 100 nm and 55 nm at super-saturations of 0.4% and 1.1%, respectively. But only slight hygroscopic growth with hygroscopic growth factors ≤1.05 was observed at RH<98% RH. At RH>98%, the hygroscopic growth increased stronger than would be expected if a constant hygroscopicity parameter for the particle/droplet solution was assumed. An increase of the hygroscopicity parameter by a factor of 4-6 was observed in the RH-range from below 90% to 99.6%, and this increase continued for increasingly diluted particle solutions for activating particles. This explains an observation already made in the past: that the relation between critical super-saturation and dry diameter for activation is steeper than what would be expected for a constant value of the hygroscopicity. Combining measurements of hygroscopic growth and activation, it was found that the surface tension that has to be assumed to interpret the measurements consistently is greater than 55 mN/m, possibly close to that of pure water, depending on the different SOA-types produced, and therefore only in part accounts for the discrepancy between hygroscopic growth and CCN activity observed for SOA particles in the past.
机译：在先前的实验室实验中研究的次要有机气溶胶（SOA）通常仅显示出轻微的吸湿性生长，但作为CCN（云凝结核）的活性要比吸湿性生长指示的好得多。这种差异在LACIS（莱比锡气溶胶云相互作用模拟器）上进行了检验，使用的是一种便携式发生器，该发生器通过α-pine烯的臭氧分解产生SOA颗粒，并在某些实验中添加丁醇或丁醇和水蒸气。干的SOA粒子的光散射信号通过LACIS光学粒子光谱仪进行测量，并用于得出1.45的SOA折射率。 LACIS还测量了高达99.6％相对湿度（RH）的SOA颗粒的吸湿性，并使用CCN计数器测量了颗粒的活化。 SOA颗粒具有CCN活性，临界直径例如为。 100 nm和55 nm的过饱和度分别为0.4％和1.1％。但是，在相对湿度<98％相对湿度下，仅观察到轻微吸湿性生长，且吸湿性生长因子≤1.05。在RH> 98％时，如果假定颗粒/液滴溶液的吸湿性参数恒定，则吸湿性增长的幅度将大于预期值。在RH范围内，吸湿性参数从90％以下增加到99.6％，增加了4-6倍，并且这种增加对于用于激活粒子的稀释粒子溶液的不断增加是持续的。这解释了过去已经观察到的现象：临界过饱和度和用于激活的干径之间的关系比恒定吸湿值所预期的陡峭。结合吸湿性生长和活化的测量结果，发现必须一致地解释测量结果的表面张力大于55 mN / m，可能接近纯水的表面张力，具体取决于所产生的不同SOA类型，因此仅部分解释了过去观察到的SOA颗粒的吸湿性增长与CCN活性之间的差异。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号