Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South China
<p>Water-soluble metals are known to produce greater adverse human health outcomes than their water-insoluble forms. Although the concentrations of water-soluble aerosol metals are usually limited by atmospheric processes that convert water-insoluble metals to water-soluble forms, factors that...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-01-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/1403/2023/acp-23-1403-2023.pdf |
| _version_ | 1797943413873573888 |
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| author | J. Yang L. Ma L. Ma X. He W. C. Au Y. Miao W.-X. Wang W.-X. Wang T. Nah T. Nah |
| author_facet | J. Yang L. Ma L. Ma X. He W. C. Au Y. Miao W.-X. Wang W.-X. Wang T. Nah T. Nah |
| author_sort | J. Yang |
| collection | DOAJ |
| description | <p>Water-soluble metals are known to produce greater adverse human health
outcomes than their water-insoluble forms. Although the concentrations of
water-soluble aerosol metals are usually limited by atmospheric processes
that convert water-insoluble metals to water-soluble forms, factors that
control the solubilities of aerosol metals in different environments remain
poorly understood. In this study, we investigated the abundance and fractional solubilities of different metals in size-fractionated aerosols
collected at an urban site in Hong Kong and identified the factors that
modulated metal solubilities in fine aerosols. The concentrations of total
and water-soluble metals in fine and coarse aerosols were the highest during the winter and spring seasons due to the long-range transport of air masses by northerly prevailing winds from emission sources located in continental areas north of Hong Kong. The study-averaged metal fractional solubilities spanned a wide range for both fine (7.8 % to 71.2 %) and coarse (0.4 % to 47.9 %) aerosols, but higher fractional solubilities were typically observed for fine aerosols. Sulfate was found to be strongly
associated with both the concentrations of water-soluble Cr, Fe, Co, Cu, Pb, and Mn and their fractional solubilities in fine aerosols, which implied that sulfate-driven acid processing likely played an important role in the dissolution of the water-insoluble forms for these six metals. Further analyses revealed that these strong associations were due to sulfate providing both the acidic environment and liquid water reaction medium needed for the acid dissolution process. Thus, the variability in the concentrations of water-soluble Cr, Fe, Co, Cu, Pb, and Mn and their
fractional solubilities were driven by both the aerosol acidity levels and
liquid water concentrations, which in turn were controlled by sulfate. These results highlight the roles that sulfate plays in the acid dissolution of metals in fine aerosols in Hong Kong. Our findings will likely also apply to other urban areas in South China, where sulfate is the dominant acidic and hygroscopic component in fine aerosols.</p> |
| first_indexed | 2024-04-10T20:23:47Z |
| format | Article |
| id | doaj.art-fca0c5cb9e7546dd96d91dc4b8504759 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-10T20:23:47Z |
| publishDate | 2023-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-fca0c5cb9e7546dd96d91dc4b85047592023-01-25T14:21:09ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-01-01231403141910.5194/acp-23-1403-2023Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South ChinaJ. Yang0L. Ma1L. Ma2X. He3W. C. Au4Y. Miao5W.-X. Wang6W.-X. Wang7T. Nah8T. Nah9School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, ChinaSchool of Energy and Environment, City University of Hong Kong, Hong Kong SAR, ChinaState Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong SAR, China College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, ChinaSchool of Energy and Environment, City University of Hong Kong, Hong Kong SAR, ChinaSchool of Energy and Environment, City University of Hong Kong, Hong Kong SAR, ChinaSchool of Energy and Environment, City University of Hong Kong, Hong Kong SAR, ChinaState Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong SAR, China School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, ChinaState Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong SAR, China <p>Water-soluble metals are known to produce greater adverse human health outcomes than their water-insoluble forms. Although the concentrations of water-soluble aerosol metals are usually limited by atmospheric processes that convert water-insoluble metals to water-soluble forms, factors that control the solubilities of aerosol metals in different environments remain poorly understood. In this study, we investigated the abundance and fractional solubilities of different metals in size-fractionated aerosols collected at an urban site in Hong Kong and identified the factors that modulated metal solubilities in fine aerosols. The concentrations of total and water-soluble metals in fine and coarse aerosols were the highest during the winter and spring seasons due to the long-range transport of air masses by northerly prevailing winds from emission sources located in continental areas north of Hong Kong. The study-averaged metal fractional solubilities spanned a wide range for both fine (7.8 % to 71.2 %) and coarse (0.4 % to 47.9 %) aerosols, but higher fractional solubilities were typically observed for fine aerosols. Sulfate was found to be strongly associated with both the concentrations of water-soluble Cr, Fe, Co, Cu, Pb, and Mn and their fractional solubilities in fine aerosols, which implied that sulfate-driven acid processing likely played an important role in the dissolution of the water-insoluble forms for these six metals. Further analyses revealed that these strong associations were due to sulfate providing both the acidic environment and liquid water reaction medium needed for the acid dissolution process. Thus, the variability in the concentrations of water-soluble Cr, Fe, Co, Cu, Pb, and Mn and their fractional solubilities were driven by both the aerosol acidity levels and liquid water concentrations, which in turn were controlled by sulfate. These results highlight the roles that sulfate plays in the acid dissolution of metals in fine aerosols in Hong Kong. Our findings will likely also apply to other urban areas in South China, where sulfate is the dominant acidic and hygroscopic component in fine aerosols.</p>https://acp.copernicus.org/articles/23/1403/2023/acp-23-1403-2023.pdf |
| spellingShingle | J. Yang L. Ma L. Ma X. He W. C. Au Y. Miao W.-X. Wang W.-X. Wang T. Nah T. Nah Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South China Atmospheric Chemistry and Physics |
| title | Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South China |
| title_full | Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South China |
| title_fullStr | Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South China |
| title_full_unstemmed | Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South China |
| title_short | Measurement report: Abundance and fractional solubilities of aerosol metals in urban Hong Kong – insights into factors that control aerosol metal dissolution in an urban site in South China |
| title_sort | measurement report abundance and fractional solubilities of aerosol metals in urban hong kong insights into factors that control aerosol metal dissolution in an urban site in south china |
| url | https://acp.copernicus.org/articles/23/1403/2023/acp-23-1403-2023.pdf |
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