I got a one-inch Talatech 24 ILD topper from SleepLikeaBear.com and the latex odor (something like vanilla, but it's not really vanilla) was strong when I unwrapped it. Very nice quality foam, good price and great service.
I aired it out in the back of my car (a hatchback) for three days, took a couple drives with the windows wide open. Sunlight came in but the UV portion was filtered out by the hatch window. This helped some, and, hoping the rest of the odor would gradually disappear, I put it on top of my 3" dunlop medium-firm latex pad (a clearance item from foamsweetfoam.com which had no smell at all) to complete my DIY latex/spring hybrid king bed.
A month later the odor remains, doesn't seem to have dissipated any more. I've aired it out a couple more times. In fact the odor permeates my down pillow, and I have to take the pillow off the bed and air it out every couple days.
It's not so bad that I can't sleep with it, but definitely aware of it. My wife doesn't seem bothered by it. Keeping my hopes up that, with time, the smell will vanish, but at the rate I've observed, it will take months.