In the case of the gypsum board, often described as 'paper-faced gypsum board', the board base is formaldehyde free. Thus, the board base is regarded as formaldehyde free and does index the climate change effects, and from this aspect, the board can be considered as having overall appealing environmental performance. Hence, the board can be considered as environmentally friendly construction material even in today's interiors. However, this does not imply that the board is environment friendly in all the cases. It too has to be scrutinized under several aspects.
The internal material is raw gypsum (calcium sulfate dihydrate) or industrial by-products gypsum like desulfurized gypsum. Calcination and dehydration creates hemihydrate gypsum, which is then mixed with water to reproduce and crystallize into a solid form. While this process encompasses both physical and chemical transformations, there is no use of adhesive based synthetic resin containing formaldehyde. This is entirely different from engineered boards, such as medium-density fiberboard and particleboard, which use very large amounts of urea-formaldehyde resin adhesives to bond the wood fibers. Hence, from the perspective of "core" of the board "formaldehyde-free" is the most appropriate description.
So, where might the environmental risks come from? While the core of gypsum board is safe, we shouldn't overlook its other components and subsequent processing steps:
Facing paper:
Both sides of the board are covered with a special heavy paper (face paper) to enhance crack and impact resistance. Some chemical additives might be added to the pulp during the fabrication of this face paper to enhance whitening, strengthen, and moisture-proofing the face paper and could contain trace levels of formaldehyde. Reputable suppliers, however, take great care as to the sourcing and quality of face paper procured and its associated formaldehyde emissions, which are insignificant and as such, well below the national safety threshold.
Adhesive:
Adhesive is used between the substrate and the face paper. Good quality will use environmentally friendly adhesives that emit next to no formaldehyde. A low price will sometimes mean the parts cut costs by using cheap glue or adhesives and these adhesives may create formaldehyde pollution.
Auxiliary materials:
This is the most easily overlooked aspect. During gypsum board installation, a large amount of adhesive (such as gypsum board adhesive) is required for gluing, caulking, and securing edges and corners. These auxiliary adhesives used on-site are often the most harmful sources of formaldehyde. Many renovation teams use low-quality construction adhesives that can contain excessive amounts of formaldehyde. Even if the board itself is environmentally friendly, contamination from these "toxic adhesives" can render the entire ceiling or partition system unhealthy.
Finishing:
After gypsum board installation, it is often finished with putty, latex paint, or wallpaper. These finishing materials themselves carry the risk of VOC emissions (including formaldehyde). Choosing low-quality putty powder and paint directly undermines the board's inherent environmental advantages.