  $^{222}Rn$ emanating from environmental dust constitutes an important
background component for many low-energy, low-rate experiments. Radon emanation
rates from dust and rock, thus, are important for experiment planning. In this
paper, we report measured radon emanation fractions for five types of dry dust
differing in grain size and composition. These data were obtained by a novel
technique in $\gamma$-spectroscopy, measuring emanated and non-emanated
$^{222}Rn$ progeny activities as well as the the parent $^{226}$Ra activity in
a time series. The range of observed radon emanation fractions is $(3.7 \pm
2.0)\%$ to $(16.2 \pm 0.9)\%$. Four of the five samples are standardized
samples available commercially, so additional investigations of these samples
may be readily carried out.
