Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign
pH is a fundamental aerosol property that affects ambient particle concentration and composition, linking pH to all aerosol environmental impacts. Here, PM<sub>1</sub> and PM<sub>2. 5</sub> pH are calculated based on data from measurements during the California Research at th...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2017-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/17/5703/2017/acp-17-5703-2017.pdf |
| _version_ | 1818544265643425792 |
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| author | H. Guo J. Liu K. D. Froyd J. M. Roberts P. R. Veres P. L. Hayes J. L. Jimenez A. Nenes R. J. Weber |
| author_facet | H. Guo J. Liu K. D. Froyd J. M. Roberts P. R. Veres P. L. Hayes J. L. Jimenez A. Nenes R. J. Weber |
| author_sort | H. Guo |
| collection | DOAJ |
| description | pH is a fundamental aerosol property that affects ambient particle
concentration and composition, linking pH to all aerosol environmental
impacts. Here, PM<sub>1</sub> and PM<sub>2. 5</sub> pH are calculated based on data from
measurements during the California Research at the Nexus of Air Quality and
Climate Change (CalNex) study from 15 May to 15 June 2010 in Pasadena, CA.
Particle pH and water were predicted with the ISORROPIA-II thermodynamic
model and validated by comparing predicted to measured gas–particle
partitioning of inorganic nitrate, ammonium, and chloride. The study mean ± standard deviation PM<sub>1</sub> pH was 1.9 ± 0.5 for the
SO<sub>4</sub><sup>2−</sup>–NO<sub>3</sub><sup>−</sup>–NH<sub>4</sub><sup>+</sup>–HNO<sub>3</sub>–NH<sub>3</sub> system. For
PM<sub>2. 5</sub>, internal mixing of sea salt components
(SO<sub>4</sub><sup>2−</sup>–NO<sub>3</sub><sup>−</sup>–NH<sub>4</sub><sup>+</sup>–Na<sup>+</sup>–Cl<sup>−</sup>–K<sup>+</sup>–HNO<sub>3</sub>–NH<sub>3</sub>–HCl
system) raised the bulk pH to 2.7 ± 0.3 and improved predicted nitric
acid partitioning with PM<sub>2. 5</sub> components. The results show little effect
of sea salt on PM<sub>1</sub> pH, but significant effects on PM<sub>2. 5</sub> pH. A mean
PM<sub>1</sub> pH of 1.9 at Pasadena was approximately one unit higher than what we
have reported in the southeastern US, despite similar temperature, relative
humidity, and sulfate ranges, and is due to higher total nitrate concentrations
(nitric acid plus nitrate) relative to sulfate, a situation where particle
water is affected by semi-volatile nitrate concentrations. Under these
conditions nitric acid partitioning can further promote nitrate formation by
increasing aerosol water, which raises pH by dilution, further increasing
nitric acid partitioning and resulting in a significant increase in fine
particle nitrate and pH. This study provides insights into the complex
interactions between particle pH and nitrate in a summertime coastal
environment and a contrast to recently reported pH in the eastern US in
summer and winter and the eastern Mediterranean. All studies have
consistently found highly acidic PM<sub>1</sub> with pH generally below 3. |
| first_indexed | 2024-12-11T22:46:14Z |
| format | Article |
| id | doaj.art-e3ae7ca149c44025911c92183d8c6a0b |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-11T22:46:14Z |
| publishDate | 2017-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-e3ae7ca149c44025911c92183d8c6a0b2022-12-22T00:47:37ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242017-05-011795703571910.5194/acp-17-5703-2017Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaignH. Guo0J. Liu1K. D. Froyd2J. M. Roberts3P. R. Veres4P. L. Hayes5J. L. Jimenez6A. Nenes7R. J. Weber8School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USASchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USAChemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, CO, USAChemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, CO, USAChemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, CO, USACooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USACooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USASchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USASchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USApH is a fundamental aerosol property that affects ambient particle concentration and composition, linking pH to all aerosol environmental impacts. Here, PM<sub>1</sub> and PM<sub>2. 5</sub> pH are calculated based on data from measurements during the California Research at the Nexus of Air Quality and Climate Change (CalNex) study from 15 May to 15 June 2010 in Pasadena, CA. Particle pH and water were predicted with the ISORROPIA-II thermodynamic model and validated by comparing predicted to measured gas–particle partitioning of inorganic nitrate, ammonium, and chloride. The study mean ± standard deviation PM<sub>1</sub> pH was 1.9 ± 0.5 for the SO<sub>4</sub><sup>2−</sup>–NO<sub>3</sub><sup>−</sup>–NH<sub>4</sub><sup>+</sup>–HNO<sub>3</sub>–NH<sub>3</sub> system. For PM<sub>2. 5</sub>, internal mixing of sea salt components (SO<sub>4</sub><sup>2−</sup>–NO<sub>3</sub><sup>−</sup>–NH<sub>4</sub><sup>+</sup>–Na<sup>+</sup>–Cl<sup>−</sup>–K<sup>+</sup>–HNO<sub>3</sub>–NH<sub>3</sub>–HCl system) raised the bulk pH to 2.7 ± 0.3 and improved predicted nitric acid partitioning with PM<sub>2. 5</sub> components. The results show little effect of sea salt on PM<sub>1</sub> pH, but significant effects on PM<sub>2. 5</sub> pH. A mean PM<sub>1</sub> pH of 1.9 at Pasadena was approximately one unit higher than what we have reported in the southeastern US, despite similar temperature, relative humidity, and sulfate ranges, and is due to higher total nitrate concentrations (nitric acid plus nitrate) relative to sulfate, a situation where particle water is affected by semi-volatile nitrate concentrations. Under these conditions nitric acid partitioning can further promote nitrate formation by increasing aerosol water, which raises pH by dilution, further increasing nitric acid partitioning and resulting in a significant increase in fine particle nitrate and pH. This study provides insights into the complex interactions between particle pH and nitrate in a summertime coastal environment and a contrast to recently reported pH in the eastern US in summer and winter and the eastern Mediterranean. All studies have consistently found highly acidic PM<sub>1</sub> with pH generally below 3.http://www.atmos-chem-phys.net/17/5703/2017/acp-17-5703-2017.pdf |
| spellingShingle | H. Guo J. Liu K. D. Froyd J. M. Roberts P. R. Veres P. L. Hayes J. L. Jimenez A. Nenes R. J. Weber Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign Atmospheric Chemistry and Physics |
| title | Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign |
| title_full | Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign |
| title_fullStr | Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign |
| title_full_unstemmed | Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign |
| title_short | Fine particle pH and gas–particle phase partitioning of inorganic species in Pasadena, California, during the 2010 CalNex campaign |
| title_sort | fine particle ph and gas particle phase partitioning of inorganic species in pasadena california during the 2010 calnex campaign |
| url | http://www.atmos-chem-phys.net/17/5703/2017/acp-17-5703-2017.pdf |
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