Boundary Layer (BL) particle formation events have been observed at many locations around the world ranging from the sub-Arctic through boreal forests to polluted industrial and coastal regions [Kulmala et al., 2004]. These events have been shown to make an important contribution to local cloud condensation nuclei (CCN) concentrations through examination of observed aerosol size distributions before and after a particle formation event [e.g., Kerminen et al., 2005]. However, the contribution of these events to CCN at regional and global scales is unknown. Here we make a first prediction of this contribution using a global aerosol model constrained by observations at continental sites throughout Europe and the US.