Quick tip. I use litter pearls. No odour at all. They absorb the moisture. All you have to do is remove the poo and stir the cat litter round to obtain the best absorption of wee. And we have a litter tray with a roof. You don't have to change the litter very often, about every three to four weeks (and that is with an indoor cat). It's initially expensive but because it lasts so long it works out cheaper.
To answer your question. Give her time. Our litter tray is tucked behind the stairs in the dining room. If we have visitors I remove the litter tray. But it never, ever smells with Litter Pearls.
http://www.crystalcle...itter/lpearls_buy.htm