What interaction occurs to define a duststorm?

A duststorm is defined primarily by the suspension of particles of sand and dust in the air, driven by strong winds. These winds lift and carry these fine particulate materials over a considerable distance, creating poor visibility and potential hazards for aircraft and ground transportation. This mechanism is characteristic of duststorms and distinguishes them from other weather phenomena.

The other choices describe different atmospheric conditions or phenomena that are not relevant to the definition of a duststorm. For instance, the first choice pertains to moisture movement, which is more about humidity and precipitation rather than wind-generated dust. The third option relates to fog, which is formed by high humidity and condensation, rather than wind-driven dust particles. The last choice addresses freezing rain, a type of winter weather that results in ice rather than dust particles being suspended in the air. Thus, the key element defining a duststorm is the presence of suspended sand particles lifted by strong winds.