Subject: Do we always need to inhale before we can smell things?

When i hold my breath i can't smell anything. Can't smell particles in the 
air reach the olfactory nerves without the help of the inhale(suck)motion? 
And if i can only smell when inhaling, why can't we smell the same 
particles when exhaling them out? If the smell is being diluted, to what 
other gases is it being diluted with? Would that mean there is always a 
large amount of gas particles in our lungs, large enough to neutralize the 
worst of smells being inhaled? And also why can't we smell our insides when 
we exhale?(i guess i mean our lungs' insides)
i ask too many questions, no? i hope you can enlighten me on some of these.  
thanks.

Re: Do we always need to inhale before we can smell things?