Abstract
The effect of incorporated aerosols on droplet pH was investigated by dissolution experiments on various particle types. These experiments conducted in an open-flow system show that the pH changes induced by aerosol solubilisation last up to 30 min, in the range of a typical droplet lifetime. These pH changes depend upon the initial pH of the experiment, i.e., the pH at cloud condensation. In the pH range between 3 and 5, the pH varies the most when it is high, since the base agents leached from the particles are neutralised by the protons present in the aqueous phase. A relationship between the neutralising capacity of the aerosol (NCA), i.e., the amount of uncompensated base species, and the pH after neutralisation has been found. Other experiments show that the NCA is related to the aerosol composition: silicates present more or less pronounced NCA, whereas C graphite presents a negative NCA, i.e., an acidifying capacity. The aerosol composition can be modified during cloud evapocondensation, notably by the addition of sulphate or sulphuric acid to the aerosol surface. NCA modification with cloud processing is observed when the amount of dissolved acid is larger than the neutralising capacity of the aerosol, i.e., when the droplet pH is less than a compensation pH characteristic of the aerosol type.
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Andreae, M. O., Charlson, R. J., Bruynseels, F., Storms, H., van Grieken, R., and Maenhaut, W., 1986: Internal mixture of sea salt, silicates, and excess sulfate in marine aerosols, Science 32, 1620–1623.
Ausset, P., Del Monte, M., and Lefèvre, R. A., 1999: Embryonic sulphated black crusts on carbonate rocks in atmospheric simulation chamber and in the field: Role of carbonaceous fly ash, Atmos. Environ. 33, 1525–1534.
Berglund, J. and Elding, L. I., 1995: Manganese-catalysed autoxidation of dissolved sulfur dioxide in the atmospheric aqueous phase, Atmos. Environ. 29, 1379–1391.
Calvert, J., Kok, L. A., Walega, Lind, and Cantrell, 1985: Chemical mechanism of acid generation in the troposphere, Nature 317, 27–35.
Clarke, A. G. and Radojevic, M., 1987: Oxidation of SO2 in acid rain chemistry, Atmos. Environ. 21, 1115–1123.
Collett Jr., J. L., Hoag, K. J., Rao X., and Pandis, S. N., 1999: Internal acid buffering in San Joaquim Valley fog drops and its influence on aerosol processing, Atmos. Environ. 33, 4833–4847.
Daum, P. H., Schwartz S. E., and Newman, L., 1984: Acidic and related constituents in liquid water stratiform clouds, J. Geophys. Res. 89, 1447–1458.
Desboeufs, K., Losno, R., Vimeux F., and Cholbi, S., 1999: pH dependent dissolution of wind transported Saharan dust, J. Geophys. Res., 104, 21287–21299.
Desboeufs, K. V., Losno R., and Colin, J. L., 2001: Factors influencing aerosol solubility during cloud processes, Atmos. Environ. 35, 3529–3537.
Graedel, T. E., Weschler, C. J., and Mandlich, M. L., 1985: Influence of transition metal complexes on atmospheric droplet acidity, Nature 317, 240–242.
Grgic, I., Poznic, M., and Bizjak, M., 1999: S(IV) autoxidation in atmospheric liquid water: The role of Fe(II) and the effect of oxalate, J. Atmos. Chem. 33, 89–102.
Hegg, D. A., 1991: Particle production in clouds, Geophys. Res. Lett. 18, 995–998.
Herut, B., Starinsky, A., Katz A., and Rosenfeld, D., 2000: Relationship between the acidity and chemical composition of rainwater and climatological conditions along a transition zone between large deserts and Mediterranean, Atmos. Environ. 34, 1281–1292.
Hobbs, P. V., 1993: Aerosol-cloud interaction, in P. V. Hobbs (ed.), Aerosol-Cloud-Climate Interaction, Washington.
Khemani, L. T., Monin, G. A., Naik, M. S., Pakasa Rao, P. S., Safai D. P., and Murty, A. S. R., 1987: Influence of alkaline particulates on pH of cloud and rain water in India, Atmos. Environ. 21, 1137–1145.
Kulshrestha, U. C., Sarkar, A. K., Srivastava S. S., and Parashar, D. C., 1996: Investigation into atmospheric deposition through precipitation studies at New Delhi (India), Atmos. Environ. 30, 4149–4154.
Larssen, T. and Carmichael, G. R., 2000: Acid rain and acidification in China: the importance of base cation deposition, Environmental Pollution 110, 89–102.
Levin, Z., Price, C., and Ganor, E., 1990: The contribution of sulfate and desert aerosols to the acidification of clouds and rain in Israel, Atmos. Environ. 24A, 1143–1151.
Li, J. and Tang, H., 1998: Acidification capacity model: Formulation and application, Water Research, 32, 3378–3386.
Losno, R., Bergametti, G., Carlier P., and Mouvier, G., 1991: Major ions in marine rainwater with attention to sources of alkaline and acidic species, Atmos. Environ. 25, 771–777.
Loÿe-Pilot, M. D., Martin J. M., and Morelli, J., 1986: Influence of Saharan dust on rain acidity and atmospheric input to the Mediterranean, Nature 321, 427–428.
Mamane, Y. and Gottlieb, J., 1992: Nitrate formation on sea-salt and mineral particles-A single particle approach, Atmos. Environ. 26A, 1763–1769.
Nguyen Hong, K., 2000: Air emission and acidity of rain water of Hanoi city, Progress in Nuclear Energy 37, 41–46.
Sanusi, A., Wortham, H., Millet M., and Mirabel, P., 1996: Chemical composition of rainwater in eastern France, Atmos. Environ. 30, 59–71.
Schwartz, S. E., 1986: Mass-transport considerations pertinent to aqueous phase reactions of gases in liquid water clouds, in Jaeschkle, W. (ed.), Chemistry of Multiphase Atmospheric Systems, NATO ASI Series, G6, Spinger-Verlag, pp. 415–471.
Singh, S. P., Satsangi, G. S., Khare, P., Lakhani, A., Maharaj Kumari, K., and Srivastava, S. S., 2001: Multiphase measurement of atmospheric ammonia, Chemosphere – Global Change Science 3, 107–116.
Spokes, L. J., Jickells T. D., and Lim, B., 1994: Solubilisation of aerosol trace metals by cloud procesing: A laboratory study, Geochimica and Cosmochimica Acta 58, 3281–3287.
Tanner, P. A., 1999: Analysis of Hong Kong daily bulk and wet deposition data from 1994 to 1995, Atmos. Environ. 33, 1757–1766.
Vong, R. J., Baker, B. M., Brechtel, F. J., Collier, R. T., Harris, J. M., Kowalski, A. S., McDonald N. C., and McInnes, L. M., 1997: Ionic and trace metals composition of cloud water collected on the Olympic peninsula of Washington State, Atmos. Environ. 31, 1991–2001.
Wurzler, S., Reisin T., and Levin, Z., 2000: Modification of mineral dust particles by cloud processing and subsequent effects on drop size distribution, J. Geophys. Res. 105, 4501–4512.
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Desboeufs, K.V., Losno, R. & Colin, J. Relationship between Droplet pH and Aerosol Dissolution Kinetics: Effect of Incorporated Aerosol Particles on Droplet pH during Cloud Processing. Journal of Atmospheric Chemistry 46, 159–172 (2003). https://doi.org/10.1023/A:1026011408748
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DOI: https://doi.org/10.1023/A:1026011408748