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Heterogeneous and catalytic uptake of ozone on mineral oxides and dusts: A Knudsen cell investigation
Author(s) -
Michel A. E.,
Usher C. R.,
Grassian V. H.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl014896
Subject(s) - ozone , loess , mineral dust , environmental chemistry , mineral , catalysis , mineralogy , environmental science , chemistry , materials science , geology , metallurgy , aerosol , geomorphology , organic chemistry
The uptake of ozone on various mineral powders has been studied using a Knudsen cell apparatus at T = 296 K. Samples included α‐Al 2 O 3 , α‐Fe 2 O 3 , SiO 2 , China loess and Saharan sand. Reactive uptake coefficients, γ BET , were measured for the various particles and found to be 8 ± 5 × 10 −5 for α‐Al 2 O 3 , 1.8 ± 0.7 × 10 −4 for α‐Fe 2 O 3 and 5 ± 3 × 10 −5 for SiO 2 . The authentic dust samples were found to have γ BET values of 2.7 ± 0.9 × 10 −5 for China loess and 6 ± 3 × 10 −5 for Saharan sand. Variations in the reactivity of the Saharan sand were observed as a function of sample treatment. Under the conditions of this study, heterogeneous uptake of ozone is catalytic and results in the destruction of ozone.