Steinbeck uses a whole raft of specific sensory details in this opening chapter to create a visceral image of the effects of the drought. Outside of the use of such specific, sense-oriented language, Steinbeck also uses personification and comparison.
In particular, Steinbeck uses comparisons to create precise images as when he writes:
"Now the dust was evenly mixed with the air; an emulsion of dust and air."
In this description, the term emulsion connotes a comparison between the sky and a liquid mixture and conjures ideas of saturation, suspension, and chemical infusion. The purpose here, again, is to create a specific image that dramatizes the physical setting of the novel.
For the most part, the language hews to the literal and the sensory.