My Stinky House

My house has been so stinky lately! I am not sure what is causing it but I have replaced the swamp cooler pads and the humidifier filters, I have left the windows open and even fed a couple of lemons to the garbage disposal and I still can not figure out what is so stinky! I am out of ideas!

The most amazing thing is... the boys room smells better than the rest house! Go figure! Any ideas on other things I can try?