Recent studies have shown that new particle formation via a secondary gas-to-particle process at coastal regions (see review articles of Kolb, 2002 and von Glasow, 2005) originates from biogenic emissions (Carpenter, 2003) of iodine-containing vapours such as CH2I2 and I2. These species undergo rapid photo-chemical reactions to produce condensable iodine oxides which, in turn lead to the nucleation and growth of new particles (O’Dowd and Hoffmann, 2005).
These particles may be ubiquitous in the Earth’s atmosphere if open ocean sources are also significant. They may influence the global radiation budget directly i.e. they can scatter and absorb solar radiation to some extent and may therefore affect climate. In terms of an indirect effect, a significant fraction of these particles have the potential to grow into cloud condensation nuclei (CCN). Changes in the number concentration of CCN may affect the number concentration and size of cloud droplets, and therefore the optical properties and the lifetime of clouds (Curtius, 2006).