The acidity of atmospheric particles and clouds
<p>Acidity, defined as pH, is a central component of aqueous chemistry. In the atmosphere, the acidity of condensed phases (aerosol particles, cloud water, and fog droplets) governs the phase partitioning of semivolatile gases such as <span class="inline-formula">HNO<sub>...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/4809/2020/acp-20-4809-2020.pdf |
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| author | H. O. T. Pye A. Nenes A. Nenes B. Alexander A. P. Ault M. C. Barth S. L. Clegg J. L. Collett Jr. K. M. Fahey C. J. Hennigan H. Herrmann M. Kanakidou J. T. Kelly I.-T. Ku V. F. McNeill N. Riemer T. Schaefer G. Shi A. Tilgner J. T. Walker T. Wang R. Weber J. Xing R. A. Zaveri A. Zuend |
| author_facet | H. O. T. Pye A. Nenes A. Nenes B. Alexander A. P. Ault M. C. Barth S. L. Clegg J. L. Collett Jr. K. M. Fahey C. J. Hennigan H. Herrmann M. Kanakidou J. T. Kelly I.-T. Ku V. F. McNeill N. Riemer T. Schaefer G. Shi A. Tilgner J. T. Walker T. Wang R. Weber J. Xing R. A. Zaveri A. Zuend |
| author_sort | H. O. T. Pye |
| collection | DOAJ |
| description | <p>Acidity, defined as pH, is a central component of aqueous
chemistry. In the atmosphere, the acidity of condensed phases (aerosol
particles, cloud water, and fog droplets) governs the phase partitioning of
semivolatile gases such as <span class="inline-formula">HNO<sub>3</sub></span>, <span class="inline-formula">NH<sub>3</sub></span>, HCl, and organic acids and
bases as well as chemical reaction rates. It has implications for the
atmospheric lifetime of pollutants, deposition, and human health. Despite
its fundamental role in atmospheric processes, only recently has this field
seen a growth in the number of studies on particle acidity. Even with this
growth, many fine-particle pH estimates must be based on thermodynamic model
calculations since no operational techniques exist for direct measurements.
Current information indicates acidic fine particles are ubiquitous, but
observationally constrained pH estimates are limited in spatial and temporal
coverage. Clouds and fogs are also generally acidic, but to a lesser degree
than particles, and have a range of pH that is quite sensitive to
anthropogenic emissions of sulfur and nitrogen oxides, as well as ambient
ammonia. Historical measurements indicate that cloud and fog droplet pH has
changed in recent decades in response to controls on anthropogenic
emissions, while the limited trend data for aerosol particles indicate
acidity may be relatively constant due to the semivolatile nature of the
key acids and bases and buffering in particles. This paper reviews and
synthesizes the current state of knowledge on the acidity of atmospheric
condensed phases, specifically particles and cloud droplets. It includes
recommendations for estimating acidity and pH, standard nomenclature, a
synthesis of current pH estimates based on observations, and new model
calculations on the local and global scale.</p> |
| first_indexed | 2024-04-13T14:41:30Z |
| format | Article |
| id | doaj.art-7f3d9f49b33e4d6c979599a82900f5af |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-13T14:41:30Z |
| publishDate | 2020-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-7f3d9f49b33e4d6c979599a82900f5af2022-12-22T02:42:53ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242020-04-01204809488810.5194/acp-20-4809-2020The acidity of atmospheric particles and cloudsH. O. T. Pye0A. Nenes1A. Nenes2B. Alexander3A. P. Ault4M. C. Barth5S. L. Clegg6J. L. Collett Jr.7K. M. Fahey8C. J. Hennigan9H. Herrmann10M. Kanakidou11J. T. Kelly12I.-T. Ku13V. F. McNeill14N. Riemer15T. Schaefer16G. Shi17A. Tilgner18J. T. Walker19T. Wang20R. Weber21J. Xing22R. A. Zaveri23A. Zuend24Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USASchool of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, 1015, SwitzerlandInstitute for Chemical Engineering Sciences, Foundation for Research and Technology Hellas, Patras, 26504, GreeceDepartment of Atmospheric Science, University of Washington, Seattle, WA 98195, USADepartment of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USANational Center for Atmospheric Research, Boulder, CO 80307, USASchool of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UKDepartment of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USAOffice of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USADepartment of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USALeibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), 04318 Leipzig, GermanyEnvironmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, Voutes, Heraklion Crete, 71003, GreeceOffice of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USADepartment of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USADepartment of Chemical Engineering, Columbia University, New York, NY 10027, USADepartment of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana-Champaign, Illinois 61801, USALeibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), 04318 Leipzig, GermanyState Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, Nankai University, Tianjin, 300071, ChinaLeibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), 04318 Leipzig, GermanyOffice of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USADepartment of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, ChinaSchool of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USASchool of Environment, Tsinghua University, Beijing, 100084, ChinaAtmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, WA 99352, USADepartment of Atmospheric and Oceanic Sciences, McGill University, Montreal, Quebec, H3A 0B9, Canada<p>Acidity, defined as pH, is a central component of aqueous chemistry. In the atmosphere, the acidity of condensed phases (aerosol particles, cloud water, and fog droplets) governs the phase partitioning of semivolatile gases such as <span class="inline-formula">HNO<sub>3</sub></span>, <span class="inline-formula">NH<sub>3</sub></span>, HCl, and organic acids and bases as well as chemical reaction rates. It has implications for the atmospheric lifetime of pollutants, deposition, and human health. Despite its fundamental role in atmospheric processes, only recently has this field seen a growth in the number of studies on particle acidity. Even with this growth, many fine-particle pH estimates must be based on thermodynamic model calculations since no operational techniques exist for direct measurements. Current information indicates acidic fine particles are ubiquitous, but observationally constrained pH estimates are limited in spatial and temporal coverage. Clouds and fogs are also generally acidic, but to a lesser degree than particles, and have a range of pH that is quite sensitive to anthropogenic emissions of sulfur and nitrogen oxides, as well as ambient ammonia. Historical measurements indicate that cloud and fog droplet pH has changed in recent decades in response to controls on anthropogenic emissions, while the limited trend data for aerosol particles indicate acidity may be relatively constant due to the semivolatile nature of the key acids and bases and buffering in particles. This paper reviews and synthesizes the current state of knowledge on the acidity of atmospheric condensed phases, specifically particles and cloud droplets. It includes recommendations for estimating acidity and pH, standard nomenclature, a synthesis of current pH estimates based on observations, and new model calculations on the local and global scale.</p>https://www.atmos-chem-phys.net/20/4809/2020/acp-20-4809-2020.pdf |
| spellingShingle | H. O. T. Pye A. Nenes A. Nenes B. Alexander A. P. Ault M. C. Barth S. L. Clegg J. L. Collett Jr. K. M. Fahey C. J. Hennigan H. Herrmann M. Kanakidou J. T. Kelly I.-T. Ku V. F. McNeill N. Riemer T. Schaefer G. Shi A. Tilgner J. T. Walker T. Wang R. Weber J. Xing R. A. Zaveri A. Zuend The acidity of atmospheric particles and clouds Atmospheric Chemistry and Physics |
| title | The acidity of atmospheric particles and clouds |
| title_full | The acidity of atmospheric particles and clouds |
| title_fullStr | The acidity of atmospheric particles and clouds |
| title_full_unstemmed | The acidity of atmospheric particles and clouds |
| title_short | The acidity of atmospheric particles and clouds |
| title_sort | acidity of atmospheric particles and clouds |
| url | https://www.atmos-chem-phys.net/20/4809/2020/acp-20-4809-2020.pdf |
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