“…Ambient and laboratory studies have shown that sulfuric acid participates in the first steps of new particle formation (Weber et al, 1996;Sihto et al, 2006;Riipinen et al, 2007;Kuang et al, 2008;Sipilä et al, 2010;Vehkamäki and Riipinen, 2012;Kulmala et al, 2013), but sulfuric acid condensation is not enough to reproduce particle growth rates observed in the ambient conditions (Kuang et al, 2010;Sipilä et al, 2010;Pierce et al, 2011Pierce et al, , 2012Riipinen et al, 2011Riipinen et al, , 2012Kulmala et al, 2013). Therefore other compounds, e.g., organics or ammonia/amines, are expected to be important in the early growth of freshly nucleated particles (O'Dowd et al, 2002;Smith et al, 2005Smith et al, , 2008Pierce et al, 2011;Riipinen et al, 2012;Vehkamäki and Riipinen, 2012;Kulmala et al, 2013).…”