Hygroscopicity of Inorganic Aerosols: Size and Relative Humidity Effects on the Growth Factor
Hygroscopicity of Inorganic Aerosols: Size and Relative Humidity Effects on the Growth Factor
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无机气溶胶的吸湿性：尺寸和相对湿度对生长因子的影响
DOI：
10.4209/aaqr.2009.12.0076
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发表时间：
2010-06-01
影响因子：
4
通讯作者：
Fang, Wen
中科院分区：
文献类型：
--
作者：
Hu, Dawei;Qiao, Liping;Fang, Wen
利用自组装吸湿串联微分迁移率分析仪（H-TDMA）系统研究了无机盐颗粒（包括（NH 4）2SO 4、NaCl、Na 2SO 4和NaNO 3）的吸湿特性。推导了等生长因子曲线，以说明初始颗粒尺寸（D 0）和相对湿度（RH）对生长因子的影响。对于粒径为100 nm的盐颗粒，测量的GFs与理论科勒曲线吻合较好。在20-200 nm范围内，（NH_4）_2SO_4、NaCl和Na_2SO_4颗粒的GF均随D_0的增大而减小，且均小于潮解RH（DRH）。然而，当RH高于DRH时，这些盐气溶胶的GF在整个研究的尺寸范围内随D 0而增加。对于NaNO 3气溶胶，虽然没有表现出突然的潮解行为，但也观察到类似的GF随D 0增加的趋势。从等生长因子曲线可以清楚地观察到，（NH_4）_2SO_4、NaCl和Na_2SO_4颗粒的生长因子都随着相对湿度的增加而增加，而在低于DRH时，随着D_0的增加而减小。在DRH以上，对于小于60 nm的颗粒，GFs对D 0更敏感，而对于大于80 nm的颗粒，GFs对RH更敏感。对于NaNO 3气溶胶，等GF曲线表明，随着RH的增加，尺寸效应变得更加突出。iso-GF曲线为盐颗粒的吸湿生长提供了清晰明确的见解。通过iso-GF曲线，我们可以清楚地阐明影响环境大气下最终粒径的主要因素。
The hygroscopic properties of inorganic salt particles, including (NH4)2SO4, NaCl, Na2SO4 and NaNO3, are investigated using a self-assembled hygroscopic tandem differential mobility analyzer (H-TDMA) system. The iso-GF (growth factor) curves are derived to illustrate the effects of the initial particle size (D0) and relative humidity (RH) on the GFs. For those salt particles of 100 nm, the GFs measured agreed well with their theoretical Kohler curves. In the size range of 20–200 nm, the GFs of (NH4)2SO4, NaCl and Na2SO4 particles all continuously decrease with D0 increasing below the deliquescence RH (DRH). However, when RH is higher than the DRH, the GFs of those salts aerosols increase with D0 throughout the investigated size range. Similar increase trend of GFs with D0 is also observed for NaNO3 aerosols though they do not exhibit the abrupt deliquescence behavior. From iso-GF curves, it can be clearly observed that the GFs of (NH4)2SO4, NaCl and Na2SO4 particles all increase with the RH while the values decrease with D0 below DRH. And above DRH, the GFs are more sensitive to D0 for particles smaller than 60 nm, while the GFs are more sensitive to RH for particles larger than 80 nm. For NaNO3 aerosols, the iso-GF curves indicate the size-effect becomes more prominent on their hygroscopicity as the RH increases. The iso-GF curves provide a lucid and explicit insight into the hygroscopic growth of salts particles. Through iso-GF curves, we can clearly elucidate the major factor that affects the ultimate particle diameter at ambient atmosphere.