When you first get your bed, definitely walk on it for a few minutes for about three days. This will help break it in and also release the "gas". The first day,we made sure that we had the overhead fan going, whole house fan going (to clear out the room of any smell) and opened a window. That first night we notice a very very faint smell, but nothing that would have kept us awake. I kept the fans on for the 2nd night also, by the third night we didn't run the fans during the day. The mattress was a little firm, but I made sure I would walk on it for the next two days, which helped a lot.
By the 4th or 5th day, the mattress was completely comfortable and I was waking up in the morning with hardly any noticable back pain. My back pain was 90% better then it was sleeping on the Sleep Number bed which we had for 13 yrs. with various toppers.
Before we got this bed I actually did NOT want to go to bed because I knew I would wake up in the morning with lots of back pain and many nights not even able to get to sleep because I was so uncomfortable. Now I can't wait to climb into bed, what a change.