Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material
This study examines the interaction of clay mineral particles and water vapor for determining the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, illite and sodium-rich montmorillonite, and an industrially derived sample, A...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | en_US |
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Copernicus GmbH on behalf of the European Geosciences Union
2014
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| Online Access: | http://hdl.handle.net/1721.1/89166 https://orcid.org/0000-0003-1851-8740 https://orcid.org/0000-0002-0828-8286 |
| _version_ | 1826188570261454848 |
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| author | Garimella, Sarvesh Huang, Y.-W. Seewald, J. S. Cziczo, Daniel James |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Garimella, Sarvesh Huang, Y.-W. Seewald, J. S. Cziczo, Daniel James |
| author_sort | Garimella, Sarvesh |
| collection | MIT |
| description | This study examines the interaction of clay mineral particles and water vapor for determining the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, illite and sodium-rich montmorillonite, and an industrially derived sample, Arizona Test Dust. Using wet and dry particle generation coupled to a differential mobility analyzer (DMA) and cloud condensation nuclei counter, the critical activation of the clay mineral particles as cloud condensation nuclei is characterized. Electron microscopy (EM) is used in order to determine non-sphericity in particle shape. It is also used in order to determine particle surface area and account for transmission of multiply charged particles by the DMA. Single particle mass spectrometry and ion chromatography are used to investigate soluble material in wet-generated samples and demonstrate that wet and dry generation yield compositionally different particles. Activation results are analyzed in the context of both κ-Köhler theory (κ-KT) and Frenkel–Halsey–Hill (FHH) adsorption activation theory. This study has two main results: (1) κ-KT is the suitable framework to describe clay mineral nucleation activity. Apparent differences in κ with respect to size arise from an artifact introduced by improper size-selection methodology. For dust particles with mobility sizes larger than ~300 nm, i.e., ones that are within an atmospherically relevant size range, both κ-KT and FHH theory yield similar critical supersaturations. However, the former requires a single hygroscopicity parameter instead of the two adjustable parameters required by the latter. For dry-generated particles, the size dependence of κ is likely an artifact of the shape of the size distribution: there is a sharp drop-off in particle concentration at ~300 nm, and a large fraction of particles classified with a mobility diameter less than ~300 nm are actually multiply charged, resulting in a much lower critical supersaturation for droplet activation than expected. For wet-generated particles, deviation from κ-KT is likely a result of the dissolution and redistribution of soluble material. (2) Wet generation is found to be unsuitable for simulating the lofting of fresh dry dust because it changes the size-dependent critical supersaturations by fractionating and re-partitioning soluble material. |
| first_indexed | 2024-09-23T08:01:44Z |
| format | Article |
| id | mit-1721.1/89166 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:01:44Z |
| publishDate | 2014 |
| publisher | Copernicus GmbH on behalf of the European Geosciences Union |
| record_format | dspace |
| spelling | mit-1721.1/891662022-09-23T10:22:59Z Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material Garimella, Sarvesh Huang, Y.-W. Seewald, J. S. Cziczo, Daniel James Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Garimella, Sarvesh Huang, Y.-W. Cziczo, Daniel James This study examines the interaction of clay mineral particles and water vapor for determining the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, illite and sodium-rich montmorillonite, and an industrially derived sample, Arizona Test Dust. Using wet and dry particle generation coupled to a differential mobility analyzer (DMA) and cloud condensation nuclei counter, the critical activation of the clay mineral particles as cloud condensation nuclei is characterized. Electron microscopy (EM) is used in order to determine non-sphericity in particle shape. It is also used in order to determine particle surface area and account for transmission of multiply charged particles by the DMA. Single particle mass spectrometry and ion chromatography are used to investigate soluble material in wet-generated samples and demonstrate that wet and dry generation yield compositionally different particles. Activation results are analyzed in the context of both κ-Köhler theory (κ-KT) and Frenkel–Halsey–Hill (FHH) adsorption activation theory. This study has two main results: (1) κ-KT is the suitable framework to describe clay mineral nucleation activity. Apparent differences in κ with respect to size arise from an artifact introduced by improper size-selection methodology. For dust particles with mobility sizes larger than ~300 nm, i.e., ones that are within an atmospherically relevant size range, both κ-KT and FHH theory yield similar critical supersaturations. However, the former requires a single hygroscopicity parameter instead of the two adjustable parameters required by the latter. For dry-generated particles, the size dependence of κ is likely an artifact of the shape of the size distribution: there is a sharp drop-off in particle concentration at ~300 nm, and a large fraction of particles classified with a mobility diameter less than ~300 nm are actually multiply charged, resulting in a much lower critical supersaturation for droplet activation than expected. For wet-generated particles, deviation from κ-KT is likely a result of the dissolution and redistribution of soluble material. (2) Wet generation is found to be unsuitable for simulating the lofting of fresh dry dust because it changes the size-dependent critical supersaturations by fractionating and re-partitioning soluble material. United States. National Oceanic and Atmospheric Administration. Climate Program Office (award number NA11OAR4310159) 2014-09-03T21:03:51Z 2014-09-03T21:03:51Z 2014-06 2014-03 Article http://purl.org/eprint/type/JournalArticle 1680-7324 http://hdl.handle.net/1721.1/89166 Garimella, S., Y.-W. Huang, J. S. Seewald, and D. J. Cziczo. “Cloud Condensation Nucleus Activity Comparison of Dry- and Wet-Generated Mineral Dust Aerosol: The Significance of Soluble Material.” Atmospheric Chemistry and Physics 14, no. 12 (June 18, 2014): 6003–6019. https://orcid.org/0000-0003-1851-8740 https://orcid.org/0000-0002-0828-8286 en_US http://dx.doi.org/10.5194/acp-14-6003-2014 Atmospheric Chemistry and Physics Creative Commons Attribution http://creativecommons.org/licenses/by/3.0/ application/pdf Copernicus GmbH on behalf of the European Geosciences Union Copernicus Publications |
| spellingShingle | Garimella, Sarvesh Huang, Y.-W. Seewald, J. S. Cziczo, Daniel James Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material |
| title | Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material |
| title_full | Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material |
| title_fullStr | Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material |
| title_full_unstemmed | Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material |
| title_short | Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material |
| title_sort | cloud condensation nucleus activity comparison of dry and wet generated mineral dust aerosol the significance of soluble material |
| url | http://hdl.handle.net/1721.1/89166 https://orcid.org/0000-0003-1851-8740 https://orcid.org/0000-0002-0828-8286 |
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