Detecting nasal snuff odors indoors versus out?

When I take certain nasal snuffs indoors, I can't discern the particular scent until I am outside. Other snuffs, I can smell them in my nasal passages right away.

I am not outdoors often lately, and I hate to waste certain snuffs more than others simply because I cannot smell them indoors. Why would this be happening, and can I remedy it?

I thought maybe the air was simply stale in my dorm room, but it's happening at home too, next to an open window.

Any thoughts?