Atmospheric Pressure Environmental (APE) Chamber for Chemical Imaging of Aerosol Samples Under Mimic Real-World Condition

ZEZHEN CHENG, Yuzhi Chen, Alexander Smith, Andrey Liyu, Ashfiqur Rahman, Carter Bracken, Swarup China, Vimal Kumar Balasubramanian, Arunima Bhattacharjee, Nurun Nahar Lata, Qian Zhao, Alla Zelenyuk, Daniel Perea, Pacific Northwest National Laboratory

     Abstract Number: 598
     Working Group: Instrumentation and Methods

Abstract
Aerosol particles affect climate directly by absorbing (warming effects) and scattering (cooling effects) incoming solar radiation and indirectly by acting as a seed for warm and cold clouds. Offline analysis of aerosol samples by scanning electron microscopy (SEM) is a critical tool to help improve our knowledge of aerosol's impact on climate by investigating chemical (e.g., elemental composition) and physical (e.g., size, and mixing state, ice nucleation activity, phase state, and hygroscopicity) of individual particles. However, SEM analysis has the significant caveat that the low-pressure (∼2×10−6 Torr) inside the chamber can cause a complete loss of water and volatile species during the chamber pumping stage, resulting in physical deformation from desiccation and misleading heterogeneous chemistry information. Therefore, a need exists for SEM analysis capability while samples exist under different, non-vacuum environmental conditions. Thus, an environmental (APE) chamber that can be integrated into the Environmental SEM (ESEM) chamber is built. More detail of the APE chamber will be provided in the presentation. We will present some preliminary SEM chemical imaging results of different types of aerosols (e.g., dust, secondary organic aerosol, and salt) retrieved from this novel APE chamber.