The interaction of N2O5 with mineral dust: aerosol flow tube and Knudsen reactor studies

• Main Authors: G. Schuster, H. de Coninck, N. Holmes, F. Hanisch, C. Wagner, J. N. Crowley
• Format: Article
• Language: English
• Published: Copernicus Publications 2008-01-01
• Series: Atmospheric Chemistry and Physics
• Online Access: http://www.atmos-chem-phys.net/8/91/2008/acp-8-91-2008.pdf

The interaction of mineral dust with N₂O₅ was investigated using both airborne mineral aerosol (using an aerosol flow reactor with variable relative humidity) and bulk samples (using a Knudsen reactor at zero humidity). Both authentic (Saharan, SDCV) and synthetic dust samples (Arizona test dust, ATD and calcite, CaCO₃) were used to derive reactive uptake coefficients (γ). The aerosol experiments (Saharan dust only) indicated efficient uptake, with e.g. a value of γ(SDCV)=(1.3&plusmn;0.2)&times;10^&minus;2 obtained at zero relative humidity. The values of γ obtained for bulk substrates in the Knudsen reactor studies are upper limits due to assumptions of available surface area, but were in reasonable agreement with the AFT measurements, with: γ(SDCV)=(3.7&plusmn;1.2)&times;10^&minus;2, γ(ATD)=(2.2&plusmn;0.8)&times;10^&minus;2 and γ(CaCO₃=(5&plusmn;2)&times;10^&minus;2. The errors quoted are statistical only. The results are compared to literature values and assessed in terms of their impact on atmospheric N₂O<sub>5</subs>.