Definition and principal sources
Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion (eg, forest/bush fires) and certain other natural processes. Thus, it may be present in substantial concentrations both indoors and outdoors.
In homes, the most significant sources of formaldehyde are likely to be pressed wood products made using adhesives that contain urea-formaldehyde (UF) resins. Pressed wood products made for indoor use include:
- Particleboard (used as sub-flooring and shelving and in cabinetry and furniture);
- Hardwood plywood paneling (used for decorative wall covering and used in cabinets and furniture);
- Medium density fiberboard (used for drawer fronts, cabinets, and furniture tops). Medium density fiberboard contains a higher resin-to-wood ratio than any other UF pressed wood products and is generally recognized as being the highest formaldehyde-emitting pressed wood product.
Formaldehyde also exists aorund the home in products such as:
- DIY products includingpaints, wallpaper and glues
- Cleaning products such as detergents, disinfectants and softeners
- Cosmetics such as liquid soaps, shampoos and nail varnish
Formaldehyde emissions are released from the combustion processes of un-vented, fuel burning appliances, like gas stoves or kerosene space heaters aswell as cigarette smoke.
The release of Formaldehyde from products reduces with time.
Formaldehyde is a colorless, pungent-smelling gas that can cause a number of adverse health effects such as:
- Watery eyes,
- Burning sensations in the eyes, nose and throat,
- Wheezing and coughing
- Breathing difficulty in some humans exposed at elevated levels (above 0.1 parts per million).
- Asthma attacks (when vulnerable people are exposed to higher concentrations).
- Skin rash
- Severe allergic reactions
There is evidence that some people can develop a sensitivity to formaldehyde. It has also been shown to cause cancer in animals and may cause cancer in humans. May also cause other effects listed under “organic gases.”
There are currently no innational standards in place for formaldehyde in composite wood products.
WHO 0.1 guidelines mg/m3 (30-minute average concentration).
China indoor air quality standard 0.1 mg/m3 a day.
The WHO conducted an investigation bringing together all the research that has been carried out into the health effects of formaldehyde at different concentrations. Below are the recommended levels to avoid health effects.
- A short-term (30-minute) guideline of 0.1 mg/m3 is recommended as preventing sensory irritation in the general population
- Proposed guideline of 0.21 mg/m3 for the protection of health for long-term effe cts, including cancer
- The lowest concentration reported to cause sensory irritation of the eyes in humans is 0.38 mg/m3 for four hours
- Increases in eye blink frequency and conjunctival redness appear at 0.6 mg/m3
US National Cancer Institute – Formaldehyde and cancer risk
EPA – Formaldehyde overview