I have a new house (about 1 year old) and last week I started to notice a VERY strong odor coming out of two main air conditioning vents. It's a 3 story house and the smell is concentrated in one spot on all three floors. It smells like a mixture of chlorine, metal and rotten eggs. The reason I think it is something coming from the air conditioning is because I have tried turning off the AC two days in a row now and the smell disipates. However, when I turn the AC back on, the smell comes back in about 4 hours. Any advice??