He can remember people's scents, the way he can remember what they look like, or the sound of their voice. @MichaelKjörling has pointed out that wolves dedicate more brain space to this than humans do, so your protagonist might have to pay attention to remember a scent, rather than it happening as automatic recall akin to a superpower. Also, the scent memories might have to compete for 'storage space' in the bit of the brain used for taste memories or visual memories.
If you overlook the lack of storage space for scents, your character could have the potential to turn into the world's greatest detective, if he can get to a crime scene pronto.
"The murderer was..." [sniff, sniff] "...a man, non-smoker, vegetarian, has recently eaten something containing garlic and chilli, washes with Pears soap and might have a beard, since I can't smell any shaving products."
So if he's NOT a detective (being an average American human), other folks are going to start to think he's a bit weird, as he might know things he shouldn't from picking up on lingering scents: Bob was just in the boss's office a few minutes ago, Mary gave Fred a ride to work, Karen has started drinking again, Janet took the stairs not the lift, John has a secret stash of sweets/drugs in his desk drawer, Eric and Doris had sex in the stationery cupboard...
He might recognise someone by scent, even if he's never met them before. So if a thief has been sneaking into his work and stealing things, your hero would immediately recognise his scent if he stood behind the thief in the supermarket checkout queue.
Meanwhile, some scents or chemicals will overwhelm him and knock out his sense of smell. A friend was stewarding at the swimming events at the Commonwealth games and said the bomb-detection sniffer dogs had to be swapped out every 10 minutes or so when they were checking the venue, since the chlorine swiftly rendered them unable to smell anything.
Wind direction will become suddenly important to him - including where the airflow from aircon ducts goes. What he can smell (unless he goes around with his nose pressed to the ground) will be very dependent on whether he is upwind or downwind.