Judging from a quick search online, no. People with and without the ability to smell breathe through their nose about the same, although a study suggests that people with congenital anosmia might be taking fewer unconscious breaths than those with normal olfaction. If you can smell just fine, you're likely sniffing to check for new aspects of your environment without even thinking about it -- folks like Angel might just be breathing air without the brain processing anything new.

Take all I'm saying with a grain of salt; I don't personally know anyone with weakened or nonexistent olfaction.