An aerosol flow tube study of the interaction of N2O5 with calcite, Arizona dust and quartz

The interaction of N2O5 with dispersed samples of Arizona Test Dust (ATD), Calcite (CaCO3) and quartz (SiO2) was investigated at varying relative humidity using an aerosol flow reactor. Reactive uptake coefficients, γ, obtained at close to zero relative humidity were (4.8 ± 0.7) × 10−3 for CaCO3, (8.6 ± 0.6) × 10−3 for Quartz and (9.8 ± 1.0) × 10−3 for ATD. In the case of calcite, evidence was obtained for an enhanced rate of uptake at relative humidities above ≈ 50%. The results are compared to literature values obtained using bulk substrates and to previous aerosol uptake data on Saharan dust.