Hygroscopicity and volatility of 4-10 nm particles during summertime atmospheric nucleation events in urban Atlanta
Hygroscopicity and volatility of 4-10 nm particles during summertime atmospheric nucleation events in urban Atlanta
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DOI：
10.1029/2005jd005918
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发表时间：
2005-11
影响因子：
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通讯作者：
H. Sakurai;Melissa A. Fink;P. Mcmurry;L. Mauldin;K. Moore;J. Smith;F. Eisele
中科院分区：
文献类型：
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作者：
H. Sakurai;Melissa A. Fink;P. Mcmurry;L. Mauldin;K. Moore;J. Smith;F. Eisele
[1]在2002年7月和8月在亚特兰大进行的气溶胶成核和实时表征实验（ANARChE）期间，用纳米串联微分迁移率分析仪（Nano TDMA）对直径为4-10 nm的大气气溶胶颗粒的吸湿性和挥发性进行了连续测量。在纳米TDMA测量中，将颗粒暴露于第一微分迁移率分析仪（DMA）下游的高湿度（约90%RH）或高温（约100°C），然后通过第二DMA调整尺寸以确定由于吸水或蒸发引起的尺寸变化。当成核发生时有几天，并且观察到高浓度的20 nm以下的颗粒，并且在这些事件期间，4-10 nm直径的颗粒非常吸湿且不挥发。这些观察结果，连同平行的热解吸化学电离质谱仪（TDCIMS）测量的亚20 nm的颗粒组成，表明颗粒主要由氨化硫酸盐。这一发现有力地支持了这样的假设，即纳米颗粒的成核和随后的生长是由本研究期间涉及硫酸和氨的反应驱动的。
[1] Continuous measurements of hygroscopicity and volatility of atmospheric aerosol particles of 4–10 nm diameter were conducted with a nanometer tandem differential mobility analyzer (Nano TDMA) during the Aerosol Nucleation and Real-time Characterization Experiment (ANARChE), which took place in Atlanta in July and August 2002. In the Nano TDMA measurements, particles were exposed to either a high humidity (∼90% RH) or an elevated temperature (∼100°C) downstream of the first differential mobility analyzer (DMA) and were then resized by the second DMA to determine the change in size due to water uptake or evaporation. There were several days when nucleation occurred and high concentrations of sub-20 nm particles were observed, and during those events, particles of 4–10 nm diameter were very hygroscopic and nonvolatile. These observations, together with parallel Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) measurements of sub-20 nm particle composition, suggest that the particles were mostly composed of ammoniated sulfates. This finding strongly supports the hypothesis that the nucleation and subsequent growth of nanoparticles were driven by reactions involving sulfuric acid and ammonia during this study.