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This content will become publicly available on April 18, 2017

Title: Measuring mass-based hygroscopicity of atmospheric particles through in situ imaging

Quantifying how atmospheric particles interact with water vapor is critical for understanding the effects of aerosols on climate. We present a novel method to measure the mass-based hygroscopicity of particles while characterizing their elemental and carbon functional group compositions. Since mass-based hygroscopicity is insensitive to particle geometry, it is advantageous for probing the hygroscopic behavior of atmospheric particles, which can have irregular morphologies. Combining scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), scanning transmission X-ray microscopy (STXM) analysis, and in situ STXM humidification experiments, this method was validated using laboratory-generated, atmospherically relevant particles. Then, the hygroscopicity and elemental composition of 15 complex atmospheric particles were analyzed by leveraging quantification of C, N, and O from STXM, and complementary elemental quantification from SEM/EDX. We found three types of hygroscopic responses, and correlated high hygroscopicity with Na and Cl content. The mixing state of 158 other particles from the sample broadly agreed with those of the humidified particles, indicating the potential to infer atmospheric hygroscopic behavior from a selected subset of particles. As a result, these methods offer unique quantitative capabilities to characterize and correlate the hygroscopicity and chemistry of individual submicrometer atmospheric particles.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [7] ;  [8] ;  [9]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Stanford Univ., Stanford, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Carl Zeiss X-ray Microscopy, Inc., Pleasanton, CA (United States)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
  4. North Carolina State Univ., Raleigh, NC (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  6. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xiamen Univ., Xiamen (China)
  7. Atmospheric Radiation Monitoring (Southern Great Plains Climate Research Facility), Billings, OK (United States)
  8. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  9. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
OSTI Identifier:
1311629
Report Number(s):
LBNL--1005926
Journal ID: ISSN 0013-936X; ir:1005926
Grant/Contract Number:
AC02-05CH11231; AC06-76RL01830
Type:
Accepted Manuscript
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 50; Journal Issue: 10; Journal ID: ISSN 0013-936X
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES aerosol water uptake; hygroscopic growth; scanning transmission X-ray microscopy; STXM; Southern Great Plains; NaCl; NaBr; (NH4)2SO4; KCl; fructose; levoglucosan