Formaldehyde is a simple, naturally occurring substance made up of hydrogen, oxygen and carbon, with the formula CH2O. It is also naturally found in all organic forms of life, in trees, fruits, vegetables, fish, plants and animals and humans.
Despite its presence in all organic life forms formaldehyde does not accumulate in the environment. In the environment it is in gaseous form, and is very quickly broken down by sunlight. It is said to have a half life of an hour, which means that over the course of one hour, the amount of formaldehyde present in the environment decreases by half. In soil and water it is also broken down very quickly but this time by bacteria rather than sunlight.
Within our bodies formaldehyde is essential in the development of DNA proteins and is a normal component of human blood. Once again however, it does not accumulate and is quickly broken down by metabolic process with formaldehyde in the body having a half life of about one minute.
Because the body is designed for dealing with formaldehyde, it is well equipped to handle additional formaldehyde intake from external sources. Most of it is exhaled from the body in our breath and the rest broken down by normal metabolic processes.