We are renters so tomorrow I will call the landlord--they are pretty good at coming to fix things. My downstairs neighbor who we share the laundry room says he thinks it is from the washer again. It smells like rotten eggs in there. It was my laundry day but I couldn't do the stairs today although I left a basket of sheets & towels down there on the floor Monday night because I ran out of energy to bring everything upstairs. So that will all need to be re-washed. The smell isn't too bad upstairs in our apt, but I can smell it. I hope it doesn't get too cold tonight--I turned off the furnace so that smell isn;t circulating throughout the house.