| Abstract
| - In this study, the heterogeneous uptake of gaseous nitric acid on dolomite, CaMg(CO3)2, and calcite, CaCO3,particles under dry conditions at 296 K was investigated. A Knudsen cell reactor was used to measureheterogeneous uptake coefficients for these reactions. Several different experiments were performed includingthose on many, single, and fractional layers of particles. For experiments using multiple particle layers, theKnudsen cell data were modeled to take into account gas diffusion into the underlying layers of the sample.From this analysis, initial heterogeneous uptake coefficients, γo,t, were determined to be (5 ± 2) × 10-4 and(2 ± 1) × 10-3, for dolomite and calcite, respectively, at a nitric acid concentration of 6.5 × 1010 moleculescm-3. For experiments that employed single or fractional particle layers, the initial heterogeneous uptakecoefficient was analyzed using a recent method described in the literature. Values of the initial heterogeneousuptake coefficient using this analysis were in agreement with the above analysis and determined to be (7 ±4) × 10-4 and (2 ± 0.4) × 10-3 for CaMg(CO3)2 and CaCO3, respectively. In addition, these results arecompared to previous literature values.
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