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Gonçalves SJ, Weis J, China S, Evangelista H, Harder TH, Müller S, Sampaio M, Laskin A, Gilles MK, Godoi RHM. Photochemical reactions on aerosols at West Antarctica: A molecular case-study of nitrate formation among sea salt aerosols. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143586. [PMID: 33218800 DOI: 10.1016/j.scitotenv.2020.143586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/09/2020] [Accepted: 10/29/2020] [Indexed: 06/11/2023]
Abstract
Environmental implications of climate change are complex and exhibit regional variations both within and between the polar regions. The increase of solar UV radiation flux over Antarctica due to stratospheric ozone depletion creates the optimal conditions for photochemical reactions on the snow. Modeling, laboratory, and indirect field studies suggest that snowpack process release gases to the atmosphere that can react on sea salt particles in remote regions such as Antarctica, modifying aerosol composition and physical properties of aerosols. Here, we present evidence of photochemical processing in West Antarctica aerosols using microscopic and chemical speciation of individual atmospheric particles. Individual aerosol particles collected at the Brazilian module Criosfera 1 were analyzed by scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS) combined with computer-controlled scanning electron microscopy (CCSEM) with energy-dispersive X-ray (EDX) microanalysis. The displacement of chlorine relative to sodium was observed over most of the sea salt particles. Particles with a chemical composition consistent with NaCl-NO3 contributed up to 30% of atmospheric particles investigated. Overall, this study provides evidence that the snowpack and particulate nitrate photolysis should be considered in dynamic partition equilibrium in the troposphere. These findings may assist in reducing modeling uncertainties and present new insights into the aerosol chemical composition in the polar environment.
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Affiliation(s)
- Sérgio J Gonçalves
- Environmental Engineering Department, Federal University of Paraná, Curitiba, PR, Brazil; LARAMG, Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ, Brazil
| | - Johannes Weis
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Chemistry, University of California, Berkeley, CA 94720, USA; Physikalisches Institüt, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Swarup China
- William R. Wiley Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Heitor Evangelista
- LARAMG, Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ, Brazil
| | - Tristan H Harder
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Chemistry, University of California, Berkeley, CA 94720, USA; Physikalisches Institüt, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Simon Müller
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Marcelo Sampaio
- Brazilian National Space Institute - INPE, São José dos Campos, SP, Brazil
| | - Alexander Laskin
- William R. Wiley Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA; Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Mary K Gilles
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ricardo H M Godoi
- Environmental Engineering Department, Federal University of Paraná, Curitiba, PR, Brazil.
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Abstract
Airborne particles are very dynamic and highly reactive components of the Earth's atmosphere. Their high surface area and water content provide a unique reaction environment for multiphase chemistry that continually modifies particle composition and properties that consequently impact air quality as well as concentrations of gas-phase species. By absorbing and scattering solar and terrestrial radiation, particles directly influence the planet's radiative balance. Their indirect effects include modifying the nucleation, lifetime, and physical properties of clouds. Due to the sensitivity of the atmospheric environment to all these variables, fundamental studies of chemical transformations of atmospheric particles, their sources, continuously evolving composition, and physical properties are of highest research priority. Accurate descriptions of particles and their effects in the atmosphere require comprehensive information not only on the particle-type populations and their size distributions and concentrations, but also on the diversity and the spatial heterogeneity of chemical components within individual particles. Developments and applications of modern chemical imaging approaches for off-line characterization of atmospheric particles have been at the forefront of modern experimental studies and have resulted in a transformative impact in atmospheric chemistry and physics. This Account presents a synopsis of recent advances in chemical imaging of atmospheric particles collected on substrates during field and laboratory experiments. The unique advantage of chemical imaging methods is that they simultaneously provide two analytical measurements: imaging of particles to assess variability in their individual sizes and morphology, as well as particle-specific speciation of their composition and spatial heterogeneity of different chemical components within individual particles. We also highlight analytical chemistry approaches that enable chemical imaging of particles with different levels of elemental and molecular specificity, including applications of multimodal methodologies where the same or similar groups of particles are probed by two or more complementary techniques. These approaches provide unique experimental insights on the nature and sources of particles, understanding their physical properties, atmospheric reactivity, and transformations. Chemical imaging data provide unique experimental input for atmospheric models that simulate aging and changes in particle-type populations, internal composition, and their associated optical and cloud forming properties. We highlight applications of chemical imaging in selected recent studies, discuss their existing limitations, and forecast future research directions for this area.
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Affiliation(s)
- Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ryan C. Moffet
- Meteorology and Air Quality Measurements, Sonoma Technology, Inc., Petaluma, California 94954, United States
| | - Mary K. Gilles
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Veghte DP, China S, Weis J, Lin P, Hinks ML, Kovarik L, Nizkorodov SA, Gilles MK, Laskin A. Heating-Induced Transformations of Atmospheric Particles: Environmental Transmission Electron Microscopy Study. Anal Chem 2018; 90:9761-9768. [PMID: 30008222 DOI: 10.1021/acs.analchem.8b01410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Environmental transmission electron microscopy was employed to probe transformations in the size, morphology, and composition of individual atmospheric particles as a function of temperature. Two different heating devices were used and calibrated in this work: a furnace heater and a Micro Electro Mechanical System heater. The temperature calibration used sublimation temperatures of NaCl, glucose, and ammonium sulfate particles, and the melting temperature of tin. Volatilization of Suwanee River Fulvic Acid was further used to validate the calibration up to 800 °C. The calibrated furnace holder was used to examine both laboratory-generated secondary organic aerosol particles and field-collected atmospheric particles. Chemical analysis by scanning transmission X-ray microscopy and near-edge fine-structure spectroscopy of the organic particles at different heating steps showed that above 300 °C particle volatilization was accompanied by charring. These methods were then applied to ambient particles collected in the central Amazon region. Distinct categories of particles differed in their volatilization response to heating. Spherical, more-viscous particles lost less volume during heating than particles that spread on the imaging substrate during impaction, due to either being liquid upon impaction or lower viscosity. This methodology illustrates a new analytical approach to accurately measure the volume fraction remaining for individually tracked atmospheric particles at elevated temperatures.
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Affiliation(s)
- Daniel P Veghte
- William R. Wiley Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , Richland , Washington 99354 , United States
| | - Swarup China
- William R. Wiley Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , Richland , Washington 99354 , United States
| | - Johannes Weis
- Department of Chemistry , University of California , Berkeley , California 94720 , United States.,Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Peng Lin
- Department of Chemistry , University of California , Irvine , California 92697 , United States
| | - Mallory L Hinks
- Department of Chemistry , University of California , Irvine , California 92697 , United States
| | - Libor Kovarik
- William R. Wiley Environmental Molecular Sciences Laboratory , Pacific Northwest National Laboratory , Richland , Washington 99354 , United States
| | - Sergey A Nizkorodov
- Department of Chemistry , University of California , Irvine , California 92697 , United States
| | - Mary K Gilles
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Alexander Laskin
- Department of Chemistry , Purdue University , West Lafayette , Indiana 47907-2084 United States
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