The uptake of N2O5 onto small sulfuric acid particles

The probabilities for N2O5 loss onto sulfuric acid aerosol (60–80 wt % H2SO4, 0.1–0.2 um radius, 230–300K) were measured using a laminar flow reactor coupled to a sulfuric acid aerosol source and a chemical ionization mass spectrometer. The aerosol morphology was extracted from measurements of the aerosol extinction of ultraviolet light (200–370nm) by using Mie theory. The reaction probabilities, γ, are large (0.06–0.12) and are comparable to probabilities measured previously under similar conditions on bulk sulfuric acid surfaces and small aerosol. These measurements confirm that the overall reaction of N2O5 with H2O in/on 60–80% sulfuric acid is fast and the uptake is due to loss very close to the liquid surface.