It wasn't odd to smell smoke in Colonel Roy Mustang's inner and outer offices. After the entire Colonel did deal with fire.
First Lieutenant Riza Hawkeye smell like a mixture of gunpowder and perfume.
The perfume was light and sometimes Roy didn't even notice she was wearing it. The gunpowder however, he could always smell. The gunpowder could be a perfume in itself.
Not that Roy minded really, he had smelled his fair share of perfume. True the most common was some sort of flowery scents but sometimes he had the pleasure of smelling other scents.
Hawkeye smelled like smoke and perhaps that was the appeal of it. Her scent was different, more subtle than all the others, which made it quite refreshing.
Besides Roy liked the scent that smoke left behind it was oddly comforting but also possess a hint of familiarity. Where there was familiarity there was comfort.