The age of your home could be a factor here. Many new homes are loaded to the gills with formaldahyde in the construction materials. This can overburden detox pathways in the liver especially in youngsters. Carpets are also very, very toxic. They are literally a toxic soup and have ruined many people's health. Anderson labs has tested many carpets and they often find that many of today's carpets are capable of even killing lab mice.
You could try creating a safe room for your children to see if this is ideed a problem. Either remove the carpeting and go with ceramic tile with a nontoxic tile set and mortar or cover the carpet with plywood and use aluminum foil backed with kraftpaper and use polyken aluminum tap for the seams. The Healthy house book I recommended from my previous post has more details. Also I hope you use a built in vacuum system otherwise you are recycling fine dust and dust mites throughout your home. One other thing. Do you humidify? This can be a bacteria/mold starter and shouild be avoided.