Do you know what formaldehyde has been used for throughout history? It has been added to insulation, it is used in pressed wood and fabrics, in glue and other adhesives. It is a fairly useful chemical, but it turns out that it is not good for human health. It can cause a lot of discomfort when you are exposed to it, and in some cases, it has even been linked to cancer.
Naturally, you want to stay away from a harmful chemical like that, but as we mentioned in the outset, it has been used in many different ways throughout history and is still being used in many products that you can find in your home. An acceptable level of formaldehyde in the air is considered to be 0.03 parts per million, but of course, a sensitive person might feel symptoms at lower levels than that. If you have a lot of older furniture that you suspect might be causing you to have the ill effects from formaldehyde, maybe it is time to get rid of them and get something new.