ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-7-1367-2007 Efficiency of cloud condensation nuclei formation from ultrafine particles Pierce J. R. 1 Adams P. J. 2 3 Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA, USA Department of Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, PA, USA 27 02 2007 7 5 1367 1379 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/7/1367/2007/acp-7-1367-2007.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/7/1367/2007/acp-7-1367-2007.pdf

Atmospheric cloud condensation nuclei (CCN) concentrations are a key uncertainty in the assessment of the effect of anthropogenic aerosol on clouds and climate. The ability of new ultrafine particles to grow to become CCN varies throughout the atmosphere and must be understood in order to understand CCN formation. We have developed the Probability of Ultrafine particle Growth (PUG) model to answer questions regarding which growth and sink mechanisms control this growth, how the growth varies between different parts of the atmosphere and how uncertainties with respect to the magnitude and size distribution of ultrafine emissions translates into uncertainty in CCN generation. The inputs to the PUG model are the concentrations of condensable gases, the size distribution of ambient aerosol, particle deposition timescales and physical properties of the particles and condensable gases. It was found in most cases that condensation is the dominant growth mechanism and coagulation with larger particles is the dominant sink mechanism for ultrafine particles. In this work we found that the probability of a new ultrafine particle generating a CCN varies from <0.1% to ~90% in different parts of the atmosphere, though in the boundary layer a large fraction of ultrafine particles have a probability between 1% and 40%. Some regions, such as the tropical free troposphere, are areas with high probabilities; however, variability within regions makes it difficult to predict which regions of the atmosphere are most efficient for generating CCN from ultrafine particles. For a given mass of primary ultrafine aerosol, an uncertainty of a factor of two in the modal diameter can lead to an uncertainty in the number of CCN generated as high as a factor for eight. It was found that no single moment of the primary aerosol size distribution, such as total mass or number, is a robust predictor of the number of CCN ultimately generated. Therefore, a complete description of the emissions size distribution is generally required for global aerosol microphysics models.

 References Adams, P. J. and Seinfeld, J. H.: Disproportionate impact of particulate emissions on global cloud condensation nuclei concentrations, Geophys. Res. Lett., 30, 1239, doi:10.1029/2002GL016303, 2003. Adams, P. J. and Seinfeld, J. H.: Predicting global aerosol size distributions in general circulation models, J. Geophys. Res., 107, 4370, doi:10.1029/2001JD001010, 2002. Albrecht, B. A.: Aerosols, Cloud Microphysics, and Fractional Cloudiness, Science, 245, 1227–1230, 1989. Andreae, M. O., Jones, C. D., and Cox, P. M.: Strong present-day aerosol cooling implies a hot future, Nature, 435, 1187–1190, 2005. Bond, T. C., Streets, D. G., Yarber, K. F., Nelson, S. M., Woo, J. H., and Klimont, Z.: A technology-based global inventory of black and organic carbon emissions from combustion, J. Geophys. Res.-Atmos., 109, D14203, doi:10.1029/2003JD003697, 2004. Charlson, R. J., Schwartz, S. E., Hales, J. M., Cess, R. D., Coakley, J. A., Hansen, J. E., and Hofman, D. J.: Climate Forcing by Anthropogenic Aerosols, Science, 255, 423–430, 1992. Clarke, A. D., Owens, S., and Zhou, J.: An ultrafine sea-salt flux from breaking waves: Implications for CCN in the remote marine atmosphere, J. Geophys. Res., 111, D06202, doi:10.1029/2005JD006565, 2006. Feingold, G. and Kreidenweis, S.: Does cloud processing of aerosol enhance droplet concentrations?, J. Geophys. Res.-Atmos., 105, 24 351–24 361, 2000. Jaenicke, R.: Tropospheric Aerosols, in: Aerosol-Cloud-Climate Interactions, edited by: Hobbs, P. V., Academic Press, San Diego, 1–31, 1993. Janhall, S., Jonsson, A. M., Molnar, P., Svensson, E. A., and Hallquist, M.: Size resolved traffic emission factors of submicrometer particles, Atmos. Environ., 38, 4331–4340, 2004. Kerminen, V. M., Lehtinen, K. E. J., Anttila, T., and Kulmala, M.: Dynamics of atmospheric nucleation mode particles: a timescale analysis, Tellus Ser. B-Chem. Phys. Meteorol., 56, 135–146, 2004. Menon, S.: Current uncertainties in assessing aerosol effects on climate, Ann. Rev. Environ. Resour., 29, 1–30, 2004. Nenes, A., Pandis, S. N., and Pilinis, C.: ISORROPIA: A new thermodynamic equilibrium model for multiphase multicomponent inorganic aerosols, Aquatic Geochem., 4, 123–152, 1998. O'Dowd, O. D., Smith, M. H., Consterdine, I. E., and Lowe, J. A.: Marine Aerosol, Sea-Salt and the Marine Sulpher Cycle: A Short Review, Atmos. Environ., 31, 73–80, 1997. Pierce, J. R. and Adams, P. J.: Global evaluation of CCN formation by direct emission of sea salt and growth of ultrafine sea salt, J. Geophys. Res.-Atmos., 111, D06203, doi:10.1029/2005JD006186, 2006. Poschl, U., Canagaratna, M., Jayne, J. T., Molina, L. T., Worsnop, D. R., Kolb, C. E., and Molina, M. J.: Mass accommodation coefficient of H2SO4 vapor on aqueous sulfuric acid surfaces and gaseous diffusion coefficient of H2SO4 in N-2/H2O, J. Phys. Chem. A, 102, 10 082–10 089, 1998. Putaud, J. P., Raes, F., Van Dingenen, R., Bruggemann, E., Facchini, M. C., Decesari, S., Fuzzi, S., Gehrig, R., Huglin, C., Laj, P., Lorbeer, G., Maenhaut, W., Mihalopoulos, N., Mulller, K., Querol, X., Rodriguez, S., Schneider, J., Spindler, G., ten Brink, H., Torseth, K., and Wiedensohler, A.: European aerosol phenomenology-2: chemical characteristics of particulate matter at kerbside, urban, rural and background sites in Europe, Atmos. Environ., 38, 2579–2595, 2004. Rissler, J., Vestin, A., Swietlicki, E., Fisch, G., Zhou, J., Artaxo, P., and Andreae, M. O.: Size distribution and hygroscopic properties of aerosol particles from dry-season biomass burning in Amazonia, Atmos. Chem. Phys., 6, 471–491, 2006. Schwartz, S. E.: Uncertainty requirements in radiative forcing of climate change, J. Air Waste Manage. Assoc., 54, 1351–1359, 2004. Seinfeld, J. H. and Pandis, S. N.: Atmospheric Chemistry and Physics, John Wiley and Sons., New York, 1998. Sotiropoulou, R. E. P., Medina, J., and Nenes, A.: CCN predictions: Is theory sufficient for assessments of the indirect effect?, Geophys. Res. Lett., 33, L05816, doi:10.1029/2005GL025148, 2006. Spracklen, D. V., Pringle, K. J., Carslaw, K. S., Chipperfield, M. P., and Mann, G. W.: A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties, Atmos. Chem. Phys., 5, 2227–2252, 2005a. Spracklen, D. V., Pringle, K. J., Carslaw, K. S., Chipperfield, M. P., and Mann, G. W.: A global off-line model of size-resolved aerosol microphysics: II. Identification of key uncertainties, Atmos. Chem. Phys., 5, 3233–3250, 2005b. Stanier, C. O., Khlystov, A. Y., and Pandis, S. N.: Ambient aerosol size distributions and number concentrations measured during the Pittsburgh Air Quality Study (PAQS), Atmos. Environ., 38, 3275–3284, 2004. Stier, P., Feichter, J., Roeckner, E., Kloster, S., and Esch, M.: Emission-induced nonlinearities in the global aerosol system, J. Climate, 19, 3845–3862, 2006. Tang, I. N. and Munkelwitz, H. R.: Water activities, densities, and refractive indices of aqueous sulfates and sodium nitrate droplets of atmospheric importance, J. Geophys. Res., 99, 18 801–18 808, 1994. Twomey, S.: The Influence of Pollution on the Shortwave Albedo of Clouds, J. Atmos. Sci., 34, 1149–1152, 1977. Twomey, S.: Pollution and the Planetary Albedo, Atmos. Environ., 8, 1251–1256, 1974. Zhang, K. M., Wexler, A. S., Niemeier, D. A., Yi, F. Z., Hinds, W. C., and Sioutas, C.: Evolution of particle number distribution near roadways. Part III: Traffic analysis and on-road size resolved particulate emission factors, Atmos. Environ., 39, 4155–4166, 2005.