Heterogeneous and catalytic uptake of ozone on mineral oxides and dusts: A Knudsen cell investigation

[1] The uptake of ozone on various mineral powders has been studied using a Knudsen cell apparatus at T = 296 K. Samples included alpha-Al2O3, alpha-Fe2O3, SiO2, China loess and Saharan sand. Reactive uptake coefficients, gamma(BET), were measured for the various particles and found to be 8 +/- 5 x 10(-5) for alpha-Al2O3, 1.8 +/- 0.7 x 10(-4) for alpha-Fe2O3 and 5 +/- 3 x 10(-5) for SiO2. The authentic dust samples were found to have gamma(BET) values of 2.7 +/- 0.9 x 10(-5) for China loess and 6 +/- 3 x 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.