The largest source of formaldehyde in homes is from resins used in adhesives and binders in engineered wood products such as particleboard, plywood, medium density fiberboard (MDF), and oriented strand board (OSB) as well as more wood finished products like engineered flooring. Other building products, such as insulation, glues and adhesives, and paints and coatings may also contain formaldehyde. There are also a variety of non-building products that contain formaldehyde such as:
- cleaning products
- textiles (e.g., permanent press fabrics)
- air fresheners
- pet care products
- bactericides and fungicides
Formaldehyde is also present in combustion processes, including tobacco and wood smoke and fuel-burning appliances such as gas stoves, kerosene space heaters, and fireplaces.
Many of the sources of formaldehyde present in residential environments are also present in commercial environments since many of the building and occupant sources are the same. In addition, some commercial facilities may generate formaldehyde in other activities or use in aqueous (water-based) solution called formalin as a disinfectant and preservative.
In addition to the building and occupant sources found in commercial buildings, industrial and manufacturing facilities may generate formaldehyde as a byproduct of their processes or activities, especially in manufacturing of industrial chemicals.
Formaldehyde is produced naturally in most living systems, including humans, as part of an oxidative metabolism. It is also produced during decay processes, as a byproduct of combustion, and during photochemical oxidation of hydrocarbons in the air (i.e., smog formation). These environmental sources result in outdoor concentrations of formaldehyde of a few ng/L in remote locations and up to approximately 20 ng/L (16 ppb) in urban locations.
Formaldehyde (CAS 50-0-0) is the smallest of the aldehydes with a chemical formula of CH2
O. It is a colorless, strong-smelling gas that readily evaporates into the air. Prism uses the acetylacetone (acac) or Hantzsch synthesis method to determine formaldehyde concentrations. This method involves the cyclization of 2,4-pentanedione (acac), ammonium acetate, and formaldehyde to form the dihydropyridine 3,5-diacetyl-1,4-dihydrolutidine (DDL) which is quantified by its fluorescence at 510 nm. This method has been correlated or is compliant with the California Air Resources Board’s (CARB) § 93120, European DIN Standard EN-717 and ASTM methods D-5582 and E-1333. It has also been compared with DNPH testing used in NIOSH 2016 and found to be in good agreement.
Comparison of Formaldehyde Testing Methods - Introduction