Extended Data Figure 4. Theoretical concentrations of negative, positive and neutral clusters during DMA ternary nucleation.

Modelled steady-state concentrations (mDMA versus nSA) at 4.0 × 10⁶ cm⁻³ [H₂SO₄], 10 p.p.t.v. DMA, 4 ion pairs cm⁻³ s⁻¹ and 278 K. a, Negative clusters. b, Positive clusters. c, Neutral clusters. A sticking probability of 0.5 is assumed for all neutral–neutral collisions and 1.0 for all charged–neutral collisions. The numbers below the centre of each circle show log₁₀C, where C (cm⁻³) is the cluster concentration (the threshold is 0.01 cm⁻³). The circle areas within each panel are proportional to C (with the exception of the DMA monomer in c).