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Petters SS, Kjærgaard ER, Hasager F, Massling A, Glasius M, Bilde M. Morphology and hygroscopicity of nanoplastics in sea spray. Phys Chem Chem Phys 2023; 25:32430-32442. [PMID: 37991397 DOI: 10.1039/d3cp03793b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
The role of airborne nanoparticles in atmospheric chemistry and public health is largely controlled by particle size, morphology, surface composition, and coating. Aerosol mass spectrometry provides real-time chemical characterization of submicron atmospheric particles, but analysis of nanoplastics in complex aerosol mixtures such as sea spray is severely limited by challenges associated with separation and ionization of the aerosol matrix. Here we characterize the internal and external mixing state of synthetic sea spray aerosols spiked with 150 nm nanoplastics. Aerosols generated from pneumatic atomization and from a sea spray tank are compared. A humidified tandem differential mobility analyzer is used as a size and hygroscopicity filter, resulting in separation of nanoplastics from sea spray, and an inline high-resolution time-of-flight aerosol mass spectrometer is used to characterize particle composition and ionization efficiency. The separation technique amplified the detection limit of the airborne nanoplastics. A salt coating was found on the nanoplastics with coating thickness increasing exponentially with increasing bulk solution salinity, which was varied from 0 to 40 g kg-1. Relative ionization efficiencies of polystyrene and sea salt chloride were 0.19 and 0.36, respectively. The growth-factor derived hygroscopicity of sea salt was 1.4 at 75% relative humidity. These results underscore the importance of separating airborne nanoplastics from sea salt aerosol for detailed online characterization by aerosol mass spectrometry and characterization of salt coatings as a function of water composition. The surface coating of nanoplastic aerosols by salts can profoundly impact their surface chemistry, water uptake, and humidified particle size distributions in the atmosphere.
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Affiliation(s)
| | | | - Freja Hasager
- Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Andreas Massling
- Department of Environmental Science, Aarhus University, DK-4000 Roskilde, Denmark
| | - Marianne Glasius
- Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Merete Bilde
- Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
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Kaluarachchi C, Or VW, Lan Y, Hasenecz ES, Kim D, Madawala CK, Dorcé GP, Mayer KJ, Sauer JS, Lee C, Cappa CD, Bertram TH, Stone EA, Prather KA, Grassian VH, Tivanski AV. Effects of Atmospheric Aging Processes on Nascent Sea Spray Aerosol Physicochemical Properties. ACS EARTH & SPACE CHEMISTRY 2022; 6:2732-2744. [PMID: 36425339 PMCID: PMC9677592 DOI: 10.1021/acsearthspacechem.2c00258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/30/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
The effects of atmospheric aging on single-particle nascent sea spray aerosol (nSSA) physicochemical properties, such as morphology, composition, phase state, and water uptake, are important to understanding their impacts on the Earth's climate. The present study investigates these properties by focusing on the aged SSA (size range of 0.1-0.6 μm) and comparing with a similar size range nSSA, both generated at a peak of a phytoplankton bloom during a mesocosm study. The aged SSAs were generated by exposing nSSA to OH radicals with exposures equivalent to 4-5 days of atmospheric aging. Complementary filter-based thermal optical analysis, atomic force microscopy (AFM), and AFM photothermal infrared spectroscopy were utilized. Both nSSA and aged SSA showed an increase in the organic mass fraction with decreasing particle sizes. In addition, aging results in a further increase of the organic mass fraction, which can be attributed to new particle formation and oxidation of volatile organic compounds followed by condensation on pre-existing particles. The results are consistent with single-particle measurements that showed a relative increase in the abundance of aged SSA core-shells with significantly higher organic coating thickness, relative to nSSA. Increased hygroscopicity was observed for aged SSA core-shells, which had more oxygenated organic species. Rounded nSSA and aged SSA had similar hygroscopicity and no apparent changes in the composition. The observed changes in aged SSA physicochemical properties showed a significant size-dependence and particle-to-particle variability. Overall, results showed that the atmospheric aging can significantly influence the nSSA physicochemical properties, thus altering the SSA effects on the climate.
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Affiliation(s)
| | - Victor W. Or
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Yiling Lan
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Elias S. Hasenecz
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Deborah Kim
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Chamika K. Madawala
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Glorianne P. Dorcé
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Kathryn J. Mayer
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Jonathan S. Sauer
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
| | - Christopher Lee
- Scripps
Institution of Oceanography, University
of California, San Diego, La Jolla, California 92093, United States
| | - Christopher D. Cappa
- Department
of Civil and Environmental Engineering, University of California, Davis, California 95616, United States
| | - Timothy H. Bertram
- Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Elizabeth A. Stone
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Kimberly A. Prather
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
- Scripps
Institution of Oceanography, University
of California, San Diego, La Jolla, California 92093, United States
| | - Vicki H. Grassian
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093, United States
- Scripps
Institution of Oceanography, University
of California, San Diego, La Jolla, California 92093, United States
| | - Alexei V. Tivanski
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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