Her captor struck a Muggle match to light a nearby candle. Wherever they were clearly didn't have any kind of working electricity. Hermione tried to soak in as much of her surroundings as possible. If the electricity wasn't working, it was most likely that they were in an abandoned building. That would explain the smell. The fact that he wasn't using magic to light the area was also another clue to his identity. He wasn't a Death Eater despite having access to a portkey. Another fugitive from the law.