I have a similar problem. The trouble is that it's not the -smell- we're allergic to. There's a component in the lingering microscopic dust. Most people think we make up the allergy because we don't like the smell, but it isn't true.
I'm going on my first cruise, and I called up NCL's toll-free number. They put me on with Customer Courtesy, where I explained we must have nothing wool, down or feather, fragrance-free sheets (having been washed only in bleach) and that the room needs to have an ionizer. They assure me they can do this.
Now, I've had allergies for my whole life and I know it will be difficult for NCL to remember to do this. I will call right before the cruise to confirm that this will be done.
For myself, I am packing several of the allergy barriers for pillowcases and mattresses. If you buy them new and pack them that way, they take up little space and will keep you from being affected by the smoke in the mattress and pillows. I also adore Dreamsack www.dreamsack.com
. This keeps anything from giving you skin allergies and the silk is VERY nice and soft.
My hope is that since it's a balcony cabin, if someone smoked in it, they had the balcony doors open. We can also keep them open, too. For the smell, charcoal filtering will work. Do not bring any aerosole sprays, those are not allowed on the ships. If you get into the cabin and it smells like a bar, I'd say find your cabin steward or the hotel manager and ask them to have it cleaned better and air-filtered. Carpets also soak it up, but as allergic as I am, unless I'm crawling on the carpet, it's usually fine.
I had asked about this on the boards, and so far only a few people have complained about smoked-in cabins, so I have my fingers crossed that the people in 0049 the weeks before me are non-smokers. I sympathize with you and hope things go ok. Nothing's worse than spending a couple thousand dollars on a vacation to have it wind up ruined.