Atmospheric Chemistry and Physics Technical Note: Use of a Beam Width Probe in an Aerosol Mass Spectrometer to Monitor Particle Collection Efficiency in the Field
Atmospheric Chemistry and Physics Technical Note: Use of a Beam Width Probe in an Aerosol Mass Spectrometer to Monitor Particle Collection Efficiency in the Field
复制标题
大气化学和物理技术说明：在气溶胶质谱仪中使用波束宽度探头监测现场颗粒收集效率
DOI：
--
复制
发表时间：
--
期刊：
影响因子：
--
通讯作者：
J. Jimenez
中科院分区：
文献类型：
--
作者：
D. Salcedo;T. Onasch;M. Canagaratna;K. Džepina;J. A. Huffman;J. Jayne;D. Worsnop;C. Kolb;S. Weimer;F. Drewnick;J. D. Allan;A. Delia;J. Jimenez
2003 年 3 月 29 日至 5 月 4 日期间，在墨西哥城大都市区实地研究 (MCMA-2003) 期间，在墨西哥城部署了两台 Aerodyne 气溶胶质谱仪 (Q-AMS)，以调查颗粒浓度、来源和过程。我们报告了在现场使用粒子束宽度探头 (BWP) 来量化由于粒子形状（非球形）和粒子尺寸引起的 AMS 内部射束展宽而导致的粒子潜在损失。来自该探测器的数据表明，没有因光束过度展宽而损失大量粒子；即，在此活动期间，AMS 的形状和尺寸相关收集效率 (E s) 约为 1。 MCMA-2003 的 BWP 数据与其他活动的比较表明，同样的结论也适用于其他几个城市、农村和偏远地区。这意味着 AMS 中的空气动力透镜能够有效地将环境颗粒聚焦成清晰的光束，并聚焦到 AMS 蒸发器上，以在各种环境中采样颗粒。 MCMA-2003 期间 AMS 测量的所有物质都具有相似的衰减曲线，这表明主导质量浓度的颗粒大部分时间都在内部混合。仅对于较小的颗粒（特别是低于 300 nm），有机和无机物质相对于颗粒尺寸表现出不同的衰减，这可能是由于这些组分的部分外部混合所致。观察到的粒子束聚焦随时间的变化可部分归因于颗粒形状（即由于相对湿度）和采样颗粒尺寸的变化。然而，成分、大气条件以及颗粒形状和尺寸之间的关系似乎非常复杂，尚未完全了解。
Two Aerodyne Aerosol Mass Spectrometers (Q-AMS) were deployed in Mexico City, during the Mexico City Metropolitan Area field study (MCMA-2003) from 29 March–4 May 2003 to investigate particle concentrations, sources, and processes. We report the use of a particle beam width probe (BWP) in the field to quantify potential losses of particles due to beam broadening inside the AMS caused by particle shape (nonsphericity) and particle size. Data from this probe show that no significant mass of particles was lost due to excessive beam broadening; i.e. the shape-and size-related collection efficiency (E s) of the AMS during this campaign was approximately one. Comparison of the BWP data from MCMA-2003 with other campaigns shows that the same conclusion holds for several other urban, rural and remotes sites. This means that the aerodynamic lens in the AMS is capable of efficiently focusing ambient particles into a well defined beam and onto the AMS vaporizer for particles sampled in a wide variety of environments. All the species measured by the AMS during MCMA-2003 have similar attenuation profiles which suggests that the particles that dominate the mass concentration were internally mixed most of the time. Only for the smaller particles (especially below 300 nm), organic and inorganic species show different attenuation versus particle size which is likely due to partial external mixing of these components. Changes observed in the focusing of the particle beam in time can be attributed, in part, to changes in particle shape (i.e. due to relative humidity) and size of the particles sampled. However, the relationships between composition, atmospheric conditions, and particle shape and size appear to be very complex and are not yet completely understood.
影响因子：
5.2
作者：
Jayne, JT;Leard, DC;Worsnop, DR
通讯作者：
Worsnop, DR