I love the butterfly pattern on her skirt, and the soft wrinkles in it and the jacket (strange as this sounds, I can almost hear them flapping?). I like how the blue grey looks against the warmer grey of the shading...
In general I dislike images with too much white but in this case it fits perfect...
Nice pose... Love the movement of the clothes and hair (especially how you can't see the eyes because the hair is covering them)... Great details!!!
Awesome use of negative space, and I'll agree with that other person to an extent - I think this is one of the best pieces you've made. "Simple" art is deceptively hard to pull off without looking unfinished or imbalanced, but this looks really well done. The lack of color adds to depth, too.
It looks like she is being smothered. (by.. the air.)
And not just because of the name, but the way her feet look planted in some doughy material (and air is doughy, it's too long to explain) and the way there is that whiteness by her chest.