The role of organic acids in new particle formation from methanesulfonic acid and methylamine

Abstract. Atmospheric organic acids (OAs) are expected to enhance methanesulfonic acid (MSA)-driven new particle formation (NPF). However, the exact role of OAs in MSA-driven NPF remains unclear. Here, we employed a two-step strategy probe MSA–methylamine (MA) NPF. Initially, evaluated enhancing potential 12 commonly detected ternary MA–MSA–OA cluster by considering free energies (MSA)1(MA)1(OA)1 clusters and atmospheric concentrations OAs. It was found that formic (ForA) has highest stabilize MA–MSA clusters. The high ForA results from its acidity, structural factors such as no intramolecular H bonds, abundance. second step is extend MSA–MA–ForA system larger sizes. indicate can indeed MSA–MA at conditions (the upper limited temperature 258.15 K), indicating might have an important effect mainly caused increased (MSA)2(MA)1 cluster, which involved pathway binary nucleation. Hence, our be required facilitate atmosphere.