In 2001, a phenomenon hit the news that had been largely hidden until that time. Drywall, imported from China and used in new home construction, was releasing sulfur compounds into the air. The toxic gasses – carbon disulfide, hydrogen sulfide and carbonyl sulfide – were generated by the drywall itself. The high sulfur content of the gypsum was reacting with moist air and releasing these chemicals.
The Consumer Product Safety Commission got involved, and finally, in early 2012, a settlement has been reached. However, this example was just the visible tip of a huge iceberg, a gourmet menu of problems with new home construction and the materials used. And homeowners were under the mistaken impression that a high quality furnace air filter would help – it doesn’t. Only a carbon air purifier, one using activated carbon filters, is able to remove these substances from the air.
Bad materials, bad outcomes
Some of the physical symptoms the Chinese drywall event caused were: chronic coughing, difficulty breathing, asthma attacks, sinus problems and headaches. An air scrubber style, carbon air purifier would have helped, but in this case, removing the bad drywall was the recommendation. But drywall isn’t the only common material that can cause problems. The CPSC lists several common culprits, each of which can release a different mix of chemicals.
- Glues used in flooring.
- Synthetic materials like carpeting, new upholstery, and items made of expanded foams.
- Composite wood products like particle board, made with glues and resins.
- Paints and sealants used.
- Construction adhesives
- Improper ventilation for combustion gases from heaters, cooking, furnaces or fire places.
Why are new homes more of a concern?
One particular problem with newly constructed homes is the lack of ventilation. Modern building standards limit air exchanges per hour (ACH) to about 1/3rd of the whole house volume. That means it would take three hours to exchange all the air in a household. Some new construction, marketed as high efficiency or energy saving homes, go to a lower ACH than this.
There are two advantages to an older home here. The first is they leak more than a new house – ACH is higher and chemicals don’t have a chance to build up as high. The second is that many of the older materials have already had a chance to bleed off the chemicals they were made with. Over time, carpets and other materials lose the volatile chemicals they contain into the household air. Over the years, this amount lessens considerably.
Of course, any new construction might turn a safe house into one with a source of airborne chemicals. And old construction may conceal other problems, such as lead based paints or asbestos.
It may be surprising to some that formaldehyde is one of the most common chemical vapors released in the home, especially new construction. Formaldehyde is used as a curing agent in industrial glues and is also generated as a breakdown product in urea foams. The CPSC lists the following as common sources:
- Pressed wood products (hardwood plywood wall paneling, particleboard, fiberboard)
- Furniture made with pressed wood/composites (most modern furniture).
- Urea-formaldehyde foam insulation (UFFI).
- Combustion sources and environmental tobacco smoke.
- Durable press drapes, other textiles, and glues.
In new construction, there are options. Talking to the builder can get important modifications installed. For example, carpeting shouldn’t be installed directly on concrete where the lining may get damp, and venting for the whole house can be increased by adding circulation fans and soffits.
Ideally, an air purifier rated to match the living space in a house will be used. These contain a carbon air purifier style filter than absorbs the chemical vapors. Other remedies include removing an offending material altogether (as with the Chinese drywall). Regular air filtration, including furnace air filter systems do not work – the chemical vapors are not trapped by even the finest of mechanical filters. The reason carbon filters work is because they present an incredible amount of surface area on a microscopic level – this is the same technology used to remove impurities from water.