An Air Atronach would be:
- generally moves around as a small windstorm, visible only for all the fallen leaves, pine needles, sticks, sand, snow, water, dirt, and pine cones it picks up.
- coalesces into a female form by compressing a lot of its kicked-up debris into recognizable shape.
The art should depict its more "solid" form. Specifically one that you might expect to find in the Falkreath or Riften holds.
But again I'm open to other ideas. For example, I've toyed with a more masculine atronach by looking at source images of the Green Man and of Japanese Oni masks. Besides, beggars can't be choosers can they?