In tightly built homes that minimize air leakage too efficiently, occupants complain of many symptoms, including breathlessness, headache, nasal stuffiness, eye irritation, coughing, frequent colds, sore throats, rashes, weakness, and insomnia. So troublesome are these complaints that many people have abandoned their new homes.
A mystery at first, the symptoms are now known to be due to the accumulation of formaldehyde vapor and other toxic gases in the home. In less tightly constructed houses, a greater exchange of air with the outdoors prevents this accumulation.
The most common source of formaldehyde in older homes is the urea-formaldehyde foam sprayed into attics and hollow walls to improve their insulation. This material should not be confused with the harmless light weight sheets of polyure-thane and polystyrene foam currently being used for insulation in the newest homes. Unlike urea-formaldehyde foam, these solid products are “cured” before use and do not give off toxic fumes unless set on fire. Even though urea-formaldehyde foam is not used in new houses, a small amount of formaldehyde seeps into them from particle board and plywood, both of which are made with formaldehyde-containing glue.
When homes are very tightly sealed, according to the Journal of the American Medical Association (245:267), we should also be concerned about volatile solvents from paint and hair sprays, carbon monoxide from wood burning stoves, and ozone from electrostatic air filters, hair dryers, and toasters. By opening some windows for a few minutes every day, you can prevent accumulation of these substances in your home.