Formaldehyde  is one of the materials used to make resins that are used in the adhesives for some composite wood products such as fiberboard, plywood, and particleboard. These are all materials that are used to make home and office furniture. It can be classified as one of the furniture chemicals.
Now here is the catch:
Formaldehyde degrades into a gas that can be inhaled. It has a very strong odor, is flammable, and is released from products made with these resins. It is present in some paints, lacquers, and coatings used in the manufacture of wooden furniture, flooring, or any other wooden artifact.
Inhaling and being exposed to formaldehyde on a regular basis is hazardous to one's health. There have been reports of formaldehyde-related health issues  stemming from cancers such as leukemia.
Because the olfactory system is the first part of the body to come into contact with formaldehyde, cancers are likely to affect the nose, throat, and sinuses.
This is a list of places you can find formaldehyde in your household :
Since formaldehyde in furniture is harmful, the level of exposure can be reduced using the following ways:
Whenever you go shopping for new furniture, ensure that you go for pieces that do not have any part made with the formaldehyde resin or coating. This way, you reduce exposure from the get-go.
Suppose you cannot get formaldehyde-free furniture; you may opt to go for older second-hand pieces of furniture. These ones have a lower emission rate since most of the formaldehyde is released into the air.
Always ensure that you open the windows every day so that you can let in fresh air into your space every day. This way, even when formaldehyde is released into the air, most of it is carried away with the wind.
Consider installing exhaust fan systems and air filtration systems to help get rid of such toxins in the air that you breathe.
Smoking simply adds levels of formaldehyde to your space. So much so, when you ensure no one smokes in your space, the levels get to reduce and remain in the safe zone.
Formaldehyde in furniture is clearly a danger to humans and your pets. And so this means that you should use the ways suggested above to ensure that the levels are kept in the safe zone to ensure you stay safe.
In a nutshell, avoid furniture that contains formaldehyde in the parts, including the paint. Also, consider getting older pieces if you cannot get formaldehyde-free furniture. Next, maintain good air ventilation in your home, and finally, install air conditioning and air filtration systems to lower the levels already in your home. If you do these, you will be able to avoid getting exposed to formaldehyde which can be detrimental to your health.