Extended Data Fig. 5: Parameterization of the HNO3–H2SO4–NH3 particle formation rate.
From: Synergistic HNO3–H2SO4–NH3 upper tropospheric particle formation
a–c Particle formation rate (J1.7) as a function of H2SO4, HNO3 and NH3 vapour concentrations, respectively, at 223 K and 25% relative humidity. The red triangles, blue circles and yellow squares represent experiments while varying only the concentration of H2SO4 (Extended Data Fig. 1), HNO3 (Fig. 1) and NH3 (Extended Data Fig. 2), respectively. The H2SO4 concentration was varied between 4.6 × 105 and 2.9 × 106 cm−3, HNO3 between 2.3 × 108 and 1.7 × 109 cm−3 and NH3 between 1.8 × 108 and 5.1 × 108 cm−3. d, The multi-acid–ammonia parameterization (black line) on the basis of equation (6) with k = 3.4 × 10−71 s−1 cm24. The grey dashed horizontal line shows a maximum of about 2 cm−3 s−1 ion-induced nucleation in the CLOUD chamber under GCR conditions, limited by the ion-pair production rate from GCR plus beam-background muons. The bars indicate 30% estimated total error on the particle formation rates, although the overall systematic scale uncertainties of −33%/+50% on sulfuric acid concentration and ±25% on nitric acid concentration are not shown. e, Temperature dependence of J1.7 for HNO3–H2SO4–NH3 nucleation (blue curve) on the basis of equation (9) with k = 2.9 × 10−98 e14,000/T s−1 cm24.
