There are three fundamental questions that are central to assessing the effect of black carbon aerosols on the climate and water cycle, that remain ill understood

1. When and how does fresh hydrophobic carbon (soot) become hydrophilic enough to serve as cloud condensation nuclei? Does chemical aging of the surface or mixing with other hydrophilic aerosol components cause this behavior?
2. What is the lifetime of black carbon in the atmosphere?
3. Can we measure in-situ black carbon reliably?

Recently limited observations suggests that current carbon aerosol transport models of carbonaceous aerosols use aging and life time constants of a day and week respectively that maybe too low by factors of up to three [1]. These changes for given emission scenario can dramatically increase their atmospheric abundances with non-linear changes in their climatic impacts. Furthermore, black carbon is a global warming agent and so climatic benefits or risks of controlling it need better quantification [2]. To help quantify atmospheric transformations, water interactions, and optical properties of black carbon (pure and mixed) we are performing single particle and bulk contact.html angle measurements.

References:

[1] Maria, S. F.; Russel, L. M.; Gilles, M. K.; Myneni, S. C. B., Organic aerosol growth mechanisms and their climate-forcing implications, Science; 10 December 2004; 306(5703), pp. 1921 - 1924.

[2] Bond, T. C.; Sun, H. L.; Can reducing black carbon emissions counteract global warming?, Env. Sci. and Techn.; 15 August 2005; 39(16), pp. 5921-5926.